30991956 has 12 divisors (see below), whose sum is σ = 72314592. Its totient is φ = 10330648.

The previous prime is 30991943. The next prime is 30991963. The reversal of 30991956 is 65919903.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

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, 1291320 + ... + 1291343.

It is an arithmetic number, because the mean of its divisors is an integer number (6026216).

Almost surely, 2^30991956 is an apocalyptic number.

It is an amenable number.

30991956 is an abundant number, since it is smaller than the sum of its proper divisors (41322636).

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

30991956 is a wasteful number, since it uses less digits than its factorization.

30991956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2582670 (or 2582668 counting only the distinct ones).

The product of its (nonzero) digits is 65610, while the sum is 42.

The square root of 30991956 is about 5567.0419434382. The cubic root of 30991956 is about 314.1108916349.

The spelling of 30991956 in words is "thirty million, nine hundred ninety-one thousand, nine hundred fifty-six".