20640677531 has 4 divisors (see below), whose sum is σ = 21727029000. Its totient is φ = 19554326064.

The previous prime is 20640677509. The next prime is 20640677557. The reversal of 20640677531 is 13577604602.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 20640677531 - 2²² = 20636483227 is a prime.

It is a super-2 number, since 2×20640677531² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20640677581) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 543175706 + ... + 543175743.

It is an arithmetic number, because the mean of its divisors is an integer number (5431757250).

Almost surely, 2^20640677531 is an apocalyptic number.

20640677531 is a deficient number, since it is larger than the sum of its proper divisors (1086351469).

20640677531 is a wasteful number, since it uses less digits than its factorization.

20640677531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1086351468.

The product of its (nonzero) digits is 211680, while the sum is 41.

The spelling of 20640677531 in words is "twenty billion, six hundred forty million, six hundred seventy-seven thousand, five hundred thirty-one".