20974578537 has 32 divisors (see below), whose sum is σ = 31800812544. Its totient is φ = 12183652800.

The previous prime is 20974578533. The next prime is 20974578601. The reversal of 20974578537 is 73587547902.

It is not a de Polignac number, because 20974578537 - 2² = 20974578533 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20974578533) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 46389 + ... + 210002.

It is an arithmetic number, because the mean of its divisors is an integer number (993775392).

Almost surely, 2^20974578537 is an apocalyptic number.

It is an amenable number.

20974578537 is a deficient number, since it is larger than the sum of its proper divisors (10826234007).

20974578537 is a wasteful number, since it uses less digits than its factorization.

20974578537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256509.

The product of its (nonzero) digits is 14817600, while the sum is 57.

The spelling of 20974578537 in words is "twenty billion, nine hundred seventy-four million, five hundred seventy-eight thousand, five hundred thirty-seven".