31631387 has 2 divisors, whose sum is σ = 31631388. Its totient is φ = 31631386.

The previous prime is 31631357. The next prime is 31631389. The reversal of 31631387 is 78313613.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31631387 - 2⁶ = 31631323 is a prime.

Together with 31631389, 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 (31631389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15815693 + 15815694.

It is an arithmetic number, because the mean of its divisors is an integer number (15815694).

Almost surely, 2^31631387 is an apocalyptic number.

31631387 is a deficient number, since it is larger than the sum of its proper divisors (1).

31631387 is an equidigital number, since it uses as much as digits as its factorization.

31631387 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9072, while the sum is 32.

The square root of 31631387 is about 5624.1787844982. The cubic root of 31631387 is about 316.2564647400.

The spelling of 31631387 in words is "thirty-one million, six hundred thirty-one thousand, three hundred eighty-seven".