31289887 has 2 divisors, whose sum is σ = 31289888. Its totient is φ = 31289886.

The previous prime is 31289857. The next prime is 31289891. The reversal of 31289887 is 78898213.

It is a strong prime.

It is an emirp because it is prime and its reverse (78898213) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31289887 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31289837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15644943 + 15644944.

It is an arithmetic number, because the mean of its divisors is an integer number (15644944).

Almost surely, 2^31289887 is an apocalyptic number.

31289887 is a deficient number, since it is larger than the sum of its proper divisors (1).

31289887 is an equidigital number, since it uses as much as digits as its factorization.

31289887 is an evil number, because the sum of its binary digits is even.

The product of its digits is 193536, while the sum is 46.

The square root of 31289887 is about 5593.7364078047. The cubic root of 31289887 is about 315.1142174197.

The spelling of 31289887 in words is "thirty-one million, two hundred eighty-nine thousand, eight hundred eighty-seven".