31506346561 has 2 divisors, whose sum is σ = 31506346562. Its totient is φ = 31506346560.

The previous prime is 31506346537. The next prime is 31506346579. The reversal of 31506346561 is 16564360513.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30942569025 + 563777536 = 175905^2 + 23744^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31506346561 is a prime.

It is not a weakly prime, because it can be changed into another prime (31506346061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15753173280 + 15753173281.

It is an arithmetic number, because the mean of its divisors is an integer number (15753173281).

Almost surely, 2^31506346561 is an apocalyptic number.

It is an amenable number.

31506346561 is a deficient number, since it is larger than the sum of its proper divisors (1).

31506346561 is an equidigital number, since it uses as much as digits as its factorization.

31506346561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 194400, while the sum is 40.

The spelling of 31506346561 in words is "thirty-one billion, five hundred six million, three hundred forty-six thousand, five hundred sixty-one".