31897986 has 8 divisors (see below), whose sum is σ = 63795984. Its totient is φ = 10632660.

The previous prime is 31897981. The next prime is 31897991. The reversal of 31897986 is 68979813.

It is an interprime number because it is at equal distance from previous prime (31897981) and next prime (31897991).

It is a sphenic number, since it is the product of 3 distinct primes.

31897986 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (31897981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2658160 + ... + 2658171.

It is an arithmetic number, because the mean of its divisors is an integer number (7974498).

Almost surely, 2^31897986 is an apocalyptic number.

31897986 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31897986 is a wasteful number, since it uses less digits than its factorization.

31897986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5316336.

The product of its digits is 653184, while the sum is 51.

The square root of 31897986 is about 5647.8302028301. The cubic root of 31897986 is about 317.1424822308.

It can be divided in two parts, 3189 and 7986, that added together give a triangular number (11175 = T₁₄₉).

The spelling of 31897986 in words is "thirty-one million, eight hundred ninety-seven thousand, nine hundred eighty-six".