31391985629 has 2 divisors, whose sum is σ = 31391985630. Its totient is φ = 31391985628.

The previous prime is 31391985593. The next prime is 31391985637. The reversal of 31391985629 is 92658919313.

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., 15744477529 + 15647508100 = 125477^2 + 125090^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31391985629 is a prime.

It is a super-3 number, since 3×31391985629³ (a number of 32 digits) contains 333 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31391985659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15695992814 + 15695992815.

It is an arithmetic number, because the mean of its divisors is an integer number (15695992815).

Almost surely, 2^31391985629 is an apocalyptic number.

It is an amenable number.

31391985629 is a deficient number, since it is larger than the sum of its proper divisors (1).

31391985629 is an equidigital number, since it uses as much as digits as its factorization.

31391985629 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3149280, while the sum is 56.

The spelling of 31391985629 in words is "thirty-one billion, three hundred ninety-one million, nine hundred eighty-five thousand, six hundred twenty-nine".