20640406216 has 32 divisors (see below), whose sum is σ = 38896640640. Its totient is φ = 10268069248.

The previous prime is 20640406207. The next prime is 20640406291. The reversal of 20640406216 is 61260404602.

It is a super-2 number, since 2×20640406216² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1797405 + ... + 1808851.

It is an arithmetic number, because the mean of its divisors is an integer number (1215520020).

Almost surely, 2^20640406216 is an apocalyptic number.

It is an amenable number.

20640406216 is a deficient number, since it is larger than the sum of its proper divisors (18256234424).

20640406216 is a wasteful number, since it uses less digits than its factorization.

20640406216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12573 (or 12569 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 31.

The spelling of 20640406216 in words is "twenty billion, six hundred forty million, four hundred six thousand, two hundred sixteen".