31686087 has 4 divisors (see below), whose sum is σ = 42248120. Its totient is φ = 21124056.

The previous prime is 31686029. The next prime is 31686101. The reversal of 31686087 is 78068613.

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

It is not a de Polignac number, because 31686087 - 2¹⁸ = 31423943 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 (31686287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5281012 + ... + 5281017.

It is an arithmetic number, because the mean of its divisors is an integer number (10562030).

Almost surely, 2^31686087 is an apocalyptic number.

31686087 is a deficient number, since it is larger than the sum of its proper divisors (10562033).

31686087 is a wasteful number, since it uses less digits than its factorization.

31686087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10562032.

The product of its (nonzero) digits is 48384, while the sum is 39.

The square root of 31686087 is about 5629.0396161335. The cubic root of 31686087 is about 316.4386600003.

The spelling of 31686087 in words is "thirty-one million, six hundred eighty-six thousand, eighty-seven".