31279979 has 2 divisors, whose sum is σ = 31279980. Its totient is φ = 31279978.

The previous prime is 31279939. The next prime is 31279981. The reversal of 31279979 is 97997213.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31279979 - 2⁸ = 31279723 is a prime.

Together with 31279981, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31279939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15639989 + 15639990.

It is an arithmetic number, because the mean of its divisors is an integer number (15639990).

Almost surely, 2^31279979 is an apocalyptic number.

31279979 is a deficient number, since it is larger than the sum of its proper divisors (1).

31279979 is an equidigital number, since it uses as much as digits as its factorization.

31279979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 214326, while the sum is 47.

The square root of 31279979 is about 5592.8507042473. The cubic root of 31279979 is about 315.0809534104.

The spelling of 31279979 in words is "thirty-one million, two hundred seventy-nine thousand, nine hundred seventy-nine".