31587987 has 4 divisors (see below), whose sum is σ = 42117320. Its totient is φ = 21058656.

The previous prime is 31587979. The next prime is 31588003. The reversal of 31587987 is 78978513.

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

It is not a de Polignac number, because 31587987 - 2³ = 31587979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31587287) 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, 5264662 + ... + 5264667.

It is an arithmetic number, because the mean of its divisors is an integer number (10529330).

Almost surely, 2^31587987 is an apocalyptic number.

31587987 is a deficient number, since it is larger than the sum of its proper divisors (10529333).

31587987 is a wasteful number, since it uses less digits than its factorization.

31587987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10529332.

The product of its digits is 423360, while the sum is 48.

The square root of 31587987 is about 5620.3191190537. The cubic root of 31587987 is about 316.1117581257. Note that the first 3 decimals are identical.

The spelling of 31587987 in words is "thirty-one million, five hundred eighty-seven thousand, nine hundred eighty-seven".