31686985 has 32 divisors (see below), whose sum is σ = 44520192. Its totient is φ = 21415680.

The previous prime is 31686983. The next prime is 31686989. The reversal of 31686985 is 58968613.

It is not a de Polignac number, because 31686985 - 2¹ = 31686983 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 9.

It is not an unprimeable number, because it can be changed into a prime (31686983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 46467 + ... + 47143.

It is an arithmetic number, because the mean of its divisors is an integer number (1391256).

Almost surely, 2^31686985 is an apocalyptic number.

It is an amenable number.

31686985 is a deficient number, since it is larger than the sum of its proper divisors (12833207).

31686985 is a wasteful number, since it uses less digits than its factorization.

31686985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 753.

The product of its digits is 311040, while the sum is 46.

The square root of 31686985 is about 5629.1193805070. The cubic root of 31686985 is about 316.4416493168.

It can be divided in two parts, 3168 and 6985, that added together give a triangular number (10153 = T₁₄₂).

The spelling of 31686985 in words is "thirty-one million, six hundred eighty-six thousand, nine hundred eighty-five".