31813518977 has 2 divisors, whose sum is σ = 31813518978. Its totient is φ = 31813518976.

The previous prime is 31813518931. The next prime is 31813519021. The reversal of 31813518977 is 77981531813.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31799448976 + 14070001 = 178324^2 + 3751^2 .

It is an emirp because it is prime and its reverse (77981531813) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31813518977 - 2²⁴ = 31796741761 is a prime.

It is not a weakly prime, because it can be changed into another prime (31813518677) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15906759488 + 15906759489.

It is an arithmetic number, because the mean of its divisors is an integer number (15906759489).

Almost surely, 2^31813518977 is an apocalyptic number.

It is an amenable number.

31813518977 is a deficient number, since it is larger than the sum of its proper divisors (1).

31813518977 is an equidigital number, since it uses as much as digits as its factorization.

31813518977 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1270080, while the sum is 53.

The spelling of 31813518977 in words is "thirty-one billion, eight hundred thirteen million, five hundred eighteen thousand, nine hundred seventy-seven".