31997171 has 2 divisors, whose sum is σ = 31997172. Its totient is φ = 31997170.

The previous prime is 31997153. The next prime is 31997183. The reversal of 31997171 is 17179913.

It is a strong prime.

It is an emirp because it is prime and its reverse (17179913) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31997171 - 2¹⁸ = 31735027 is a prime.

It is not a weakly prime, because it can be changed into another prime (31997131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15998585 + 15998586.

It is an arithmetic number, because the mean of its divisors is an integer number (15998586).

Almost surely, 2^31997171 is an apocalyptic number.

31997171 is a deficient number, since it is larger than the sum of its proper divisors (1).

31997171 is an equidigital number, since it uses as much as digits as its factorization.

31997171 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11907, while the sum is 38.

The square root of 31997171 is about 5656.6041933301. The cubic root of 31997171 is about 317.4708543730.

The spelling of 31997171 in words is "thirty-one million, nine hundred ninety-seven thousand, one hundred seventy-one".