21164265704 has 32 divisors (see below), whose sum is σ = 40985653320. Its totient is φ = 10240229376.

The previous prime is 21164265701. The next prime is 21164265709. The reversal of 21164265704 is 40756246112.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 20081724100 + 1082541604 = 141710^2 + 32902^2 .

It is a super-2 number, since 2×21164265704² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21164265701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 310937 + ... + 372840.

Almost surely, 2^21164265704 is an apocalyptic number.

It is an amenable number.

21164265704 is a deficient number, since it is larger than the sum of its proper divisors (19821387616).

21164265704 is a wasteful number, since it uses less digits than its factorization.

21164265704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 683909 (or 683905 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 38.

The spelling of 21164265704 in words is "twenty-one billion, one hundred sixty-four million, two hundred sixty-five thousand, seven hundred four".