21052604 has 12 divisors (see below), whose sum is σ = 36960504. Its totient is φ = 10492464.

The previous prime is 21052597. The next prime is 21052609. The reversal of 21052604 is 40625012.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21052609) 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, 7034 + ... + 9569.

It is an arithmetic number, because the mean of its divisors is an integer number (3080042).

Almost surely, 2^21052604 is an apocalyptic number.

It is an amenable number.

21052604 is a deficient number, since it is larger than the sum of its proper divisors (15907900).

21052604 is a wasteful number, since it uses less digits than its factorization.

21052604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16924 (or 16922 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 21052604 is about 4588.3116720641. The cubic root of 21052604 is about 276.1225913431.

Adding to 21052604 its reverse (40625012), we get a palindrome (61677616).

The spelling of 21052604 in words is "twenty-one million, fifty-two thousand, six hundred four".