211821120 has 504 divisors, whose sum is σ = 903427200. Its totient is φ = 45287424.

The previous prime is 211821119. The next prime is 211821121. The reversal of 211821120 is 21128112.

It is an interprime number because it is at equal distance from previous prime (211821119) and next prime (211821121).

It is a tau number, because it is divible by the number of its divisors (504).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 211821093 and 211821102.

It is not an unprimeable number, because it can be changed into a prime (211821121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 2681241 + ... + 2681319.

Almost surely, 2^211821120 is an apocalyptic number.

211821120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 211821120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (451713600).

211821120 is an abundant number, since it is smaller than the sum of its proper divisors (691606080).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

211821120 is a wasteful number, since it uses less digits than its factorization.

211821120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135 (or 115 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 211821120 is about 14554.0757178187. The cubic root of 211821120 is about 596.1054420595.

Adding to 211821120 its reverse (21128112), we get a palindrome (232949232).

The spelling of 211821120 in words is "two hundred eleven million, eight hundred twenty-one thousand, one hundred twenty".