31319987 has 2 divisors, whose sum is σ = 31319988. Its totient is φ = 31319986.

The previous prime is 31319983. The next prime is 31320007. The reversal of 31319987 is 78991313.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 31319987 - 2² = 31319983 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31319983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15659993 + 15659994.

It is an arithmetic number, because the mean of its divisors is an integer number (15659994).

Almost surely, 2^31319987 is an apocalyptic number.

31319987 is a deficient number, since it is larger than the sum of its proper divisors (1).

31319987 is an equidigital number, since it uses as much as digits as its factorization.

31319987 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 31319987 is about 5596.4262703979. The cubic root of 31319987 is about 315.2152287374.

The spelling of 31319987 in words is "thirty-one million, three hundred nineteen thousand, nine hundred eighty-seven".