31973987 has 4 divisors (see below), whose sum is σ = 32165616. Its totient is φ = 31782360.

The previous prime is 31973971. The next prime is 31973993. The reversal of 31973987 is 78937913.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 31973987 - 2⁴ = 31973971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31970987) 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, 95564 + ... + 95897.

It is an arithmetic number, because the mean of its divisors is an integer number (8041404).

Almost surely, 2^31973987 is an apocalyptic number.

31973987 is a deficient number, since it is larger than the sum of its proper divisors (191629).

31973987 is a wasteful number, since it uses less digits than its factorization.

31973987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191628.

The product of its digits is 285768, while the sum is 47.

The square root of 31973987 is about 5654.5545359471. The cubic root of 31973987 is about 317.3941598567.

It can be divided in two parts, 3 and 1973987, that multiplied together give a triangular number (5921961 = T₃₄₄₁).

The spelling of 31973987 in words is "thirty-one million, nine hundred seventy-three thousand, nine hundred eighty-seven".