31879391 has 2 divisors, whose sum is σ = 31879392. Its totient is φ = 31879390.

The previous prime is 31879373. The next prime is 31879399. The reversal of 31879391 is 19397813.

It is a strong prime.

It is an emirp because it is prime and its reverse (19397813) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31879391 - 2⁶ = 31879327 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31879399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15939695 + 15939696.

It is an arithmetic number, because the mean of its divisors is an integer number (15939696).

Almost surely, 2^31879391 is an apocalyptic number.

31879391 is a deficient number, since it is larger than the sum of its proper divisors (1).

31879391 is an equidigital number, since it uses as much as digits as its factorization.

31879391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40824, while the sum is 41.

The square root of 31879391 is about 5646.1837554228. The cubic root of 31879391 is about 317.0808439530.

The spelling of 31879391 in words is "thirty-one million, eight hundred seventy-nine thousand, three hundred ninety-one".