31997207 has 4 divisors (see below), whose sum is σ = 34906056. Its totient is φ = 29088360.

The previous prime is 31997201. The next prime is 31997221. The reversal of 31997207 is 70279913.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 70279913 = 11 ⋅6389083.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31997207 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31997201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1454408 + ... + 1454429.

It is an arithmetic number, because the mean of its divisors is an integer number (8726514).

Almost surely, 2^31997207 is an apocalyptic number.

31997207 is a deficient number, since it is larger than the sum of its proper divisors (2908849).

31997207 is a wasteful number, since it uses less digits than its factorization.

31997207 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2908848.

The product of its (nonzero) digits is 23814, while the sum is 38.

The square root of 31997207 is about 5656.6073754504. The cubic root of 31997207 is about 317.4709734350.

The spelling of 31997207 in words is "thirty-one million, nine hundred ninety-seven thousand, two hundred seven".