31981079 has 4 divisors (see below), whose sum is σ = 34441176. Its totient is φ = 29520984.

The previous prime is 31981073. The next prime is 31981087. The reversal of 31981079 is 97018913.

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-31981079 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 (31981073) 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, 1230029 + ... + 1230054.

It is an arithmetic number, because the mean of its divisors is an integer number (8610294).

Almost surely, 2^31981079 is an apocalyptic number.

31981079 is a deficient number, since it is larger than the sum of its proper divisors (2460097).

31981079 is a wasteful number, since it uses less digits than its factorization.

31981079 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2460096.

The product of its (nonzero) digits is 13608, while the sum is 38.

The square root of 31981079 is about 5655.1816062793. The cubic root of 31981079 is about 317.4176246916.

The spelling of 31981079 in words is "thirty-one million, nine hundred eighty-one thousand, seventy-nine".