31977691 has 4 divisors (see below), whose sum is σ = 33080400. Its totient is φ = 30874984.

The previous prime is 31977679. The next prime is 31977707. The reversal of 31977691 is 19677913.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31977691 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31977601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 551311 + ... + 551368.

It is an arithmetic number, because the mean of its divisors is an integer number (8270100).

Almost surely, 2^31977691 is an apocalyptic number.

31977691 is a deficient number, since it is larger than the sum of its proper divisors (1102709).

31977691 is a wasteful number, since it uses less digits than its factorization.

31977691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1102708.

The product of its digits is 71442, while the sum is 43.

The square root of 31977691 is about 5654.8820500520. The cubic root of 31977691 is about 317.4064154711.

The spelling of 31977691 in words is "thirty-one million, nine hundred seventy-seven thousand, six hundred ninety-one".