31997129 has 2 divisors, whose sum is σ = 31997130. Its totient is φ = 31997128.

The previous prime is 31997113. The next prime is 31997131. The reversal of 31997129 is 92179913.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23863225 + 8133904 = 4885^2 + 2852^2 .

It is a cyclic number.

It is not a de Polignac number, because 31997129 - 2⁴ = 31997113 is a prime.

Together with 31997131, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31997149) 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, 15998564 + 15998565.

It is an arithmetic number, because the mean of its divisors is an integer number (15998565).

Almost surely, 2^31997129 is an apocalyptic number.

It is an amenable number.

31997129 is a deficient number, since it is larger than the sum of its proper divisors (1).

31997129 is an equidigital number, since it uses as much as digits as its factorization.

31997129 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30618, while the sum is 41.

The square root of 31997129 is about 5656.6004808542. The cubic root of 31997129 is about 317.4707154671.

The spelling of 31997129 in words is "thirty-one million, nine hundred ninety-seven thousand, one hundred twenty-nine".