21026321604 has 48 divisors (see below), whose sum is σ = 54578675200. Its totient is φ = 7000289568.

The previous prime is 21026321593. The next prime is 21026321681. The reversal of 21026321604 is 40612362012.

21026321604 is a `hidden beast` number, since 2 + 1 + 0 + 26 + 32 + 1 + 604 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27892 + ... + 206955.

Almost surely, 2^21026321604 is an apocalyptic number.

It is an amenable number.

21026321604 is an abundant number, since it is smaller than the sum of its proper divisors (33552353596).

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

21026321604 is a wasteful number, since it uses less digits than its factorization.

21026321604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235689 (or 235681 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

Adding to 21026321604 its reverse (40612362012), we get a palindrome (61638683616).

The spelling of 21026321604 in words is "twenty-one billion, twenty-six million, three hundred twenty-one thousand, six hundred four".