21212000 has 48 divisors (see below), whose sum is σ = 52127712. Its totient is φ = 8483200.

The previous prime is 21211997. The next prime is 21212017. The reversal of 21212000 is 21212.

It is a Harshad number since it is a multiple of its sum of digits (8).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1349 + ... + 6651.

It is an arithmetic number, because the mean of its divisors is an integer number (1085994).

Almost surely, 2^21212000 is an apocalyptic number.

21212000 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 21212000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26063856).

21212000 is an abundant number, since it is smaller than the sum of its proper divisors (30915712).

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

21212000 is an equidigital number, since it uses as much as digits as its factorization.

21212000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5328 (or 5310 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 8.

The square root of 21212000 is about 4605.6487056657. The cubic root of 21212000 is about 276.8177107850.

Adding to 21212000 its reverse (21212), we get a palindrome (21233212).

21212000 divided by its reverse (21212) gives a cube (1000 = 10³).

The spelling of 21212000 in words is "twenty-one million, two hundred twelve thousand".