31997887 has 2 divisors, whose sum is σ = 31997888. Its totient is φ = 31997886.

The previous prime is 31997873. The next prime is 31997909. The reversal of 31997887 is 78879913.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 31997887 - 2¹¹ = 31995839 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31997827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15998943 + 15998944.

It is an arithmetic number, because the mean of its divisors is an integer number (15998944).

Almost surely, 2^31997887 is an apocalyptic number.

31997887 is a deficient number, since it is larger than the sum of its proper divisors (1).

31997887 is an equidigital number, since it uses as much as digits as its factorization.

31997887 is an evil number, because the sum of its binary digits is even.

The product of its digits is 762048, while the sum is 52.

The square root of 31997887 is about 5656.6674818306. The cubic root of 31997887 is about 317.4732223681.

The spelling of 31997887 in words is "thirty-one million, nine hundred ninety-seven thousand, eight hundred eighty-seven".