21297579264 has 144 divisors (see below), whose sum is σ = 67825643200. Its totient is φ = 6553073664.

The previous prime is 21297579241. The next prime is 21297579283. The reversal of 21297579264 is 46297579212.

21297579264 is a `hidden beast` number, since 2 + 1 + 2 + 9 + 7 + 579 + 2 + 64 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 21297579264.

It is a congruent number.

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, 28654 + ... + 208365.

Almost surely, 2^21297579264 is an apocalyptic number.

21297579264 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21297579264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33912821600).

21297579264 is an abundant number, since it is smaller than the sum of its proper divisors (46528063936).

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

21297579264 is a wasteful number, since it uses less digits than its factorization.

21297579264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 237057 (or 237037 counting only the distinct ones).

The product of its digits is 3810240, while the sum is 54.

The spelling of 21297579264 in words is "twenty-one billion, two hundred ninety-seven million, five hundred seventy-nine thousand, two hundred sixty-four".