31909642691 has 2 divisors, whose sum is σ = 31909642692. Its totient is φ = 31909642690.

The previous prime is 31909642657. The next prime is 31909642693. The reversal of 31909642691 is 19624690913.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31909642691 - 2³⁰ = 30835900867 is a prime.

Together with 31909642693, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31909642693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15954821345 + 15954821346.

It is an arithmetic number, because the mean of its divisors is an integer number (15954821346).

Almost surely, 2^31909642691 is an apocalyptic number.

31909642691 is a deficient number, since it is larger than the sum of its proper divisors (1).

31909642691 is an equidigital number, since it uses as much as digits as its factorization.

31909642691 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 629856, while the sum is 50.

The spelling of 31909642691 in words is "thirty-one billion, nine hundred nine million, six hundred forty-two thousand, six hundred ninety-one".