87187931 has 4 divisors (see below), whose sum is σ = 88238472. Its totient is φ = 86137392.

The previous prime is 87187921. The next prime is 87187937. The reversal of 87187931 is 13978178.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87187931 is a prime.

It is a super-2 number, since 2×87187931² = 15203470624121522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (87187937) 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, 525146 + ... + 525311.

It is an arithmetic number, because the mean of its divisors is an integer number (22059618).

Almost surely, 2^87187931 is an apocalyptic number.

87187931 is a deficient number, since it is larger than the sum of its proper divisors (1050541).

87187931 is a wasteful number, since it uses less digits than its factorization.

87187931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1050540.

The product of its digits is 84672, while the sum is 44.

The square root of 87187931 is about 9337.4477776317. The cubic root of 87187931 is about 443.4235868159.

The spelling of 87187931 in words is "eighty-seven million, one hundred eighty-seven thousand, nine hundred thirty-one".