21155200 has 96 divisors (see below), whose sum is σ = 57105720. Its totient is φ = 7680000.

The previous prime is 21155179. The next prime is 21155201. The reversal of 21155200 is 255112.

It is a hoax number, since the sum of its digits (16) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155201) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 34900 + ... + 35500.

Almost surely, 2^21155200 is an apocalyptic number.

21155200 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 21155200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28552860).

21155200 is an abundant number, since it is smaller than the sum of its proper divisors (35950520).

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

21155200 is a wasteful number, since it uses less digits than its factorization.

21155200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 636 (or 619 counting only the distinct ones).

The product of its (nonzero) digits is 100, while the sum is 16.

The square root of 21155200 is about 4599.4782312780. The cubic root of 21155200 is about 276.5704089262.

It can be divided in two parts, 2 and 1155200, that multiplied together give a square (2310400 = 1520²).

The spelling of 21155200 in words is "twenty-one million, one hundred fifty-five thousand, two hundred".