31371188861 has 2 divisors, whose sum is σ = 31371188862. Its totient is φ = 31371188860.

The previous prime is 31371188851. The next prime is 31371188887. The reversal of 31371188861 is 16888117313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20622683236 + 10748505625 = 143606^2 + 103675^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31371188861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31371188801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15685594430 + 15685594431.

It is an arithmetic number, because the mean of its divisors is an integer number (15685594431).

Almost surely, 2^31371188861 is an apocalyptic number.

It is an amenable number.

31371188861 is a deficient number, since it is larger than the sum of its proper divisors (1).

31371188861 is an equidigital number, since it uses as much as digits as its factorization.

31371188861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 193536, while the sum is 47.

The spelling of 31371188861 in words is "thirty-one billion, three hundred seventy-one million, one hundred eighty-eight thousand, eight hundred sixty-one".