31693813 has 2 divisors, whose sum is σ = 31693814. Its totient is φ = 31693812.

The previous prime is 31693801. The next prime is 31693817. The reversal of 31693813 is 31839613.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31281649 + 412164 = 5593^2 + 642^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31693813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31693817) 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, 15846906 + 15846907.

It is an arithmetic number, because the mean of its divisors is an integer number (15846907).

Almost surely, 2^31693813 is an apocalyptic number.

It is an amenable number.

31693813 is a deficient number, since it is larger than the sum of its proper divisors (1).

31693813 is an equidigital number, since it uses as much as digits as its factorization.

31693813 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11664, while the sum is 34.

The square root of 31693813 is about 5629.7258370191. The cubic root of 31693813 is about 316.4643769278.

The spelling of 31693813 in words is "thirty-one million, six hundred ninety-three thousand, eight hundred thirteen".