21523604 has 12 divisors (see below), whose sum is σ = 37699200. Its totient is φ = 10752408.

The previous prime is 21523591. The next prime is 21523609. The reversal of 21523604 is 40632512.

It is a self number, because there is not a number n which added to its sum of digits gives 21523604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21523609) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6557 + ... + 9275.

It is an arithmetic number, because the mean of its divisors is an integer number (3141600).

Almost surely, 2^21523604 is an apocalyptic number.

It is an amenable number.

21523604 is a deficient number, since it is larger than the sum of its proper divisors (16175596).

21523604 is a wasteful number, since it uses less digits than its factorization.

21523604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4702 (or 4700 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 21523604 is about 4639.3538343179. The cubic root of 21523604 is about 278.1666099256.

The spelling of 21523604 in words is "twenty-one million, five hundred twenty-three thousand, six hundred four".