31378979 has 4 divisors (see below), whose sum is σ = 31405584. Its totient is φ = 31352376.

The previous prime is 31378961. The next prime is 31378987. The reversal of 31378979 is 97987313.

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-31378979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31378909) 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, 11447 + ... + 13920.

It is an arithmetic number, because the mean of its divisors is an integer number (7851396).

Almost surely, 2^31378979 is an apocalyptic number.

31378979 is a deficient number, since it is larger than the sum of its proper divisors (26605).

31378979 is a wasteful number, since it uses less digits than its factorization.

31378979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26604.

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

The square root of 31378979 is about 5601.6942972640. The cubic root of 31378979 is about 315.4130099407.

The spelling of 31378979 in words is "thirty-one million, three hundred seventy-eight thousand, nine hundred seventy-nine".