31689157 has 2 divisors, whose sum is σ = 31689158. Its totient is φ = 31689156.

The previous prime is 31689149. The next prime is 31689247. The reversal of 31689157 is 75198613.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27552001 + 4137156 = 5249^2 + 2034^2 .

It is a cyclic number.

It is not a de Polignac number, because 31689157 - 2³ = 31689149 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31689137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15844578 + 15844579.

It is an arithmetic number, because the mean of its divisors is an integer number (15844579).

Almost surely, 2^31689157 is an apocalyptic number.

It is an amenable number.

31689157 is a deficient number, since it is larger than the sum of its proper divisors (1).

31689157 is an equidigital number, since it uses as much as digits as its factorization.

31689157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 45360, while the sum is 40.

The square root of 31689157 is about 5629.3123025819. The cubic root of 31689157 is about 316.4488793679.

The spelling of 31689157 in words is "thirty-one million, six hundred eighty-nine thousand, one hundred fifty-seven".