31997217 has 16 divisors (see below), whose sum is σ = 48909312. Its totient is φ = 18227280.

The previous prime is 31997201. The next prime is 31997221. The reversal of 31997217 is 71279913.

It is not a de Polignac number, because 31997217 - 2⁴ = 31997201 is a prime.

It is not an unprimeable number, because it can be changed into a prime (31997227) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5092 + ... + 9482.

It is an arithmetic number, because the mean of its divisors is an integer number (3056832).

Almost surely, 2^31997217 is an apocalyptic number.

It is an amenable number.

31997217 is a deficient number, since it is larger than the sum of its proper divisors (16912095).

31997217 is a wasteful number, since it uses less digits than its factorization.

31997217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4748.

The product of its digits is 23814, while the sum is 39.

The square root of 31997217 is about 5656.6082593724. The cubic root of 31997217 is about 317.4710065078.

The spelling of 31997217 in words is "thirty-one million, nine hundred ninety-seven thousand, two hundred seventeen".