31139887 has 4 divisors (see below), whose sum is σ = 31442320. Its totient is φ = 30837456.

The previous prime is 31139863. The next prime is 31139891. The reversal of 31139887 is 78893113.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 31139887 - 2¹¹ = 31137839 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31139807) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 151062 + ... + 151267.

It is an arithmetic number, because the mean of its divisors is an integer number (7860580).

Almost surely, 2^31139887 is an apocalyptic number.

31139887 is a deficient number, since it is larger than the sum of its proper divisors (302433).

31139887 is a wasteful number, since it uses less digits than its factorization.

31139887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 302432.

The product of its digits is 36288, while the sum is 40.

The square root of 31139887 is about 5580.3124464496. The cubic root of 31139887 is about 314.6098705954.

The spelling of 31139887 in words is "thirty-one million, one hundred thirty-nine thousand, eight hundred eighty-seven".