31865987 has 2 divisors, whose sum is σ = 31865988. Its totient is φ = 31865986.

The previous prime is 31865929. The next prime is 31866001. The reversal of 31865987 is 78956813.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31865987 - 2⁸ = 31865731 is a prime.

It is a super-2 number, since 2×31865987² = 2030882254968338, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31865927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15932993 + 15932994.

It is an arithmetic number, because the mean of its divisors is an integer number (15932994).

Almost surely, 2^31865987 is an apocalyptic number.

31865987 is a deficient number, since it is larger than the sum of its proper divisors (1).

31865987 is an equidigital number, since it uses as much as digits as its factorization.

31865987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 362880, while the sum is 47.

The square root of 31865987 is about 5644.9966341885. The cubic root of 31865987 is about 317.0363978149.

The spelling of 31865987 in words is "thirty-one million, eight hundred sixty-five thousand, nine hundred eighty-seven".