21255604 has 12 divisors (see below), whose sum is σ = 39155200. Its totient is φ = 10068408.

The previous prime is 21255587. The next prime is 21255607. The reversal of 21255604 is 40655212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21255607) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 139764 + ... + 139915.

Almost surely, 2^21255604 is an apocalyptic number.

It is an amenable number.

21255604 is a deficient number, since it is larger than the sum of its proper divisors (17899596).

21255604 is a wasteful number, since it uses less digits than its factorization.

21255604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 279702 (or 279700 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 21255604 is about 4610.3800277201. The cubic root of 21255604 is about 277.0072591250.

The spelling of 21255604 in words is "twenty-one million, two hundred fifty-five thousand, six hundred four".