21275974956 has 48 divisors (see below), whose sum is σ = 50179209696. Its totient is φ = 7015593984.

The previous prime is 21275974939. The next prime is 21275974969. The reversal of 21275974956 is 65947957212.

It is a super-2 number, since 2×21275974956² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21275974896 and 21275974905.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4836550 + ... + 4840946.

It is an arithmetic number, because the mean of its divisors is an integer number (1045400202).

Almost surely, 2^21275974956 is an apocalyptic number.

It is an amenable number.

21275974956 is an abundant number, since it is smaller than the sum of its proper divisors (28903234740).

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

21275974956 is a wasteful number, since it uses less digits than its factorization.

21275974956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8658 (or 8656 counting only the distinct ones).

The product of its digits is 9525600, while the sum is 57.

The spelling of 21275974956 in words is "twenty-one billion, two hundred seventy-five million, nine hundred seventy-four thousand, nine hundred fifty-six".