21529331964 has 72 divisors (see below), whose sum is σ = 65854440288. Its totient is φ = 5789399040.

The previous prime is 21529331959. The next prime is 21529331987. The reversal of 21529331964 is 46913392512.

21529331964 is a `hidden beast` number, since 2 + 1 + 529 + 3 + 31 + 96 + 4 = 666.

It is a super-2 number, since 2×21529331964² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2508477 + ... + 2517044.

It is an arithmetic number, because the mean of its divisors is an integer number (914645004).

Almost surely, 2^21529331964 is an apocalyptic number.

It is an amenable number.

21529331964 is an abundant number, since it is smaller than the sum of its proper divisors (44325108324).

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

21529331964 is a wasteful number, since it uses less digits than its factorization.

21529331964 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5025555 (or 5025550 counting only the distinct ones).

The product of its digits is 349920, while the sum is 45.

The spelling of 21529331964 in words is "twenty-one billion, five hundred twenty-nine million, three hundred thirty-one thousand, nine hundred sixty-four".