20977993964 has 12 divisors (see below), whose sum is σ = 36743063784. Its totient is φ = 10479975744.

The previous prime is 20977993951. The next prime is 20977993979. The reversal of 20977993964 is 46939977902.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 20977993964.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2250077 + ... + 2259380.

It is an arithmetic number, because the mean of its divisors is an integer number (3061921982).

Almost surely, 2^20977993964 is an apocalyptic number.

It is an amenable number.

20977993964 is a deficient number, since it is larger than the sum of its proper divisors (15765069820).

20977993964 is a wasteful number, since it uses less digits than its factorization.

20977993964 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4510624 (or 4510622 counting only the distinct ones).

The product of its (nonzero) digits is 46294416, while the sum is 65.

The spelling of 20977993964 in words is "twenty billion, nine hundred seventy-seven million, nine hundred ninety-three thousand, nine hundred sixty-four".