31909642657 has 2 divisors, whose sum is σ = 31909642658. Its totient is φ = 31909642656.

The previous prime is 31909642621. The next prime is 31909642691. The reversal of 31909642657 is 75624690913.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17957072016 + 13952570641 = 134004^2 + 118121^2 .

It is an emirp because it is prime and its reverse (75624690913) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31909642657 is a prime.

It is not a weakly prime, because it can be changed into another prime (31909642697) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15954821328 + 15954821329.

It is an arithmetic number, because the mean of its divisors is an integer number (15954821329).

Almost surely, 2^31909642657 is an apocalyptic number.

It is an amenable number.

31909642657 is a deficient number, since it is larger than the sum of its proper divisors (1).

31909642657 is an equidigital number, since it uses as much as digits as its factorization.

31909642657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2449440, while the sum is 52.

The spelling of 31909642657 in words is "thirty-one billion, nine hundred nine million, six hundred forty-two thousand, six hundred fifty-seven".