31312157 has 2 divisors, whose sum is σ = 31312158. Its totient is φ = 31312156.

The previous prime is 31312123. The next prime is 31312163. The reversal of 31312157 is 75121313.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31292836 + 19321 = 5594^2 + 139^2 .

It is a cyclic number.

It is not a de Polignac number, because 31312157 - 2¹² = 31308061 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31312117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15656078 + 15656079.

It is an arithmetic number, because the mean of its divisors is an integer number (15656079).

Almost surely, 2^31312157 is an apocalyptic number.

It is an amenable number.

31312157 is a deficient number, since it is larger than the sum of its proper divisors (1).

31312157 is an equidigital number, since it uses as much as digits as its factorization.

31312157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 630, while the sum is 23.

The square root of 31312157 is about 5595.7266730962. The cubic root of 31312157 is about 315.1889586015.

The spelling of 31312157 in words is "thirty-one million, three hundred twelve thousand, one hundred fifty-seven".