31316861 has 2 divisors, whose sum is σ = 31316862. Its totient is φ = 31316860.

The previous prime is 31316849. The next prime is 31316881. The reversal of 31316861 is 16861313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31292836 + 24025 = 5594^2 + 155^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31316861 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is equal to p_1934309 and since 31316861 and 1934309 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31316821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15658430 + 15658431.

It is an arithmetic number, because the mean of its divisors is an integer number (15658431).

Almost surely, 2^31316861 is an apocalyptic number.

It is an amenable number.

31316861 is a deficient number, since it is larger than the sum of its proper divisors (1).

31316861 is an equidigital number, since it uses as much as digits as its factorization.

31316861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 29.

The square root of 31316861 is about 5596.1469780555. The cubic root of 31316861 is about 315.2047413385.

The spelling of 31316861 in words is "thirty-one million, three hundred sixteen thousand, eight hundred sixty-one".