31320640402565 has 4 divisors (see below), whose sum is σ = 37584768483084. Its totient is φ = 25056512322048.

The previous prime is 31320640402537. The next prime is 31320640402567. The reversal of 31320640402565 is 56520404602313.

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

It can be written as a sum of positive squares in 2 ways, for example, as 14448870561889 + 16871769840676 = 3801167^2 + 4107526^2 .

It is a cyclic number.

It is not a de Polignac number, because 31320640402565 - 2¹⁰ = 31320640401541 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31320640402567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3132064040252 + ... + 3132064040261.

It is an arithmetic number, because the mean of its divisors is an integer number (9396192120771).

Almost surely, 2^{31320640402565} is an apocalyptic number.

It is an amenable number.

31320640402565 is a deficient number, since it is larger than the sum of its proper divisors (6264128080519).

31320640402565 is an equidigital number, since it uses as much as digits as its factorization.

31320640402565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6264128080518.

The product of its (nonzero) digits is 518400, while the sum is 41.

The spelling of 31320640402565 in words is "thirty-one trillion, three hundred twenty billion, six hundred forty million, four hundred two thousand, five hundred sixty-five".