21255200 has 54 divisors (see below), whose sum is σ = 52209549. Its totient is φ = 8449920.

The previous prime is 21255161. The next prime is 21255203. The reversal of 21255200 is 255212.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 2 ways, for example, as 20830096 + 425104 = 4564^2 + 652^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=3260.

It is a hoax number, since the sum of its digits (17) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21255203) 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 8 ways as a sum of consecutive naturals, for example, 130319 + ... + 130481.

Almost surely, 2^21255200 is an apocalyptic number.

21255200 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 21255200

21255200 is an abundant number, since it is smaller than the sum of its proper divisors (30954349).

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

21255200 is an equidigital number, since it uses as much as digits as its factorization.

21255200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 346 (or 170 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 17.

The square root of 21255200 is about 4610.3362133363. The cubic root of 21255200 is about 277.0055041111.

Multiplying 21255200 by its product of nonzero digits (200), we get a square (4251040000 = 65200²).

21255200 divided by its product of nonzero digits (200) gives a square (106276 = 326²).

The spelling of 21255200 in words is "twenty-one million, two hundred fifty-five thousand, two hundred".