20640256716 has 48 divisors (see below), whose sum is σ = 51036090336. Its totient is φ = 6469976064.

The previous prime is 20640256673. The next prime is 20640256727. The reversal of 20640256716 is 61765204602.

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, 206700 + ... + 289836.

It is an arithmetic number, because the mean of its divisors is an integer number (1063251882).

Almost surely, 2^20640256716 is an apocalyptic number.

It is an amenable number.

20640256716 is an abundant number, since it is smaller than the sum of its proper divisors (30395833620).

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

20640256716 is a wasteful number, since it uses less digits than its factorization.

20640256716 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84378 (or 84376 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 39.

The spelling of 20640256716 in words is "twenty billion, six hundred forty million, two hundred fifty-six thousand, seven hundred sixteen".