31867987 has 2 divisors, whose sum is σ = 31867988. Its totient is φ = 31867986.

The previous prime is 31867943. The next prime is 31867993. The reversal of 31867987 is 78976813.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31867987 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31867987.

It is not a weakly prime, because it can be changed into another prime (31867387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15933993 + 15933994.

It is an arithmetic number, because the mean of its divisors is an integer number (15933994).

Almost surely, 2^31867987 is an apocalyptic number.

31867987 is a deficient number, since it is larger than the sum of its proper divisors (1).

31867987 is an equidigital number, since it uses as much as digits as its factorization.

31867987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 508032, while the sum is 49.

The square root of 31867987 is about 5645.1737794332. The cubic root of 31867987 is about 317.0430303782.

The spelling of 31867987 in words is "thirty-one million, eight hundred sixty-seven thousand, nine hundred eighty-seven".