31086981 has 6 divisors (see below), whose sum is σ = 44903430. Its totient is φ = 20724648.

The previous prime is 31086971. The next prime is 31086989. The reversal of 31086981 is 18968013.

It can be written as a sum of positive squares in only one way, i.e., 21538881 + 9548100 = 4641^2 + 3090^2 .

It is not a de Polignac number, because 31086981 - 2⁵ = 31086949 is a prime.

It is a super-2 number, since 2×31086981² = 1932800775388722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31086989) 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 5 ways as a sum of consecutive naturals, for example, 1727046 + ... + 1727063.

It is an arithmetic number, because the mean of its divisors is an integer number (7483905).

Almost surely, 2^31086981 is an apocalyptic number.

It is an amenable number.

31086981 is a deficient number, since it is larger than the sum of its proper divisors (13816449).

31086981 is a wasteful number, since it uses less digits than its factorization.

31086981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3454115 (or 3454112 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 31086981 is about 5575.5700157024. The cubic root of 31086981 is about 314.4315977896.

The spelling of 31086981 in words is "thirty-one million, eighty-six thousand, nine hundred eighty-one".