30991912 has 48 divisors (see below), whose sum is σ = 68136660. Its totient is φ = 13176576.

The previous prime is 30991897. The next prime is 30991913. The reversal of 30991912 is 21919903.

It can be written as a sum of positive squares in 2 ways, for example, as 25260676 + 5731236 = 5026^2 + 2394^2 .

It is not an unprimeable number, because it can be changed into a prime (30991913) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 67588 + ... + 68044.

Almost surely, 2^30991912 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 30991912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34068330).

30991912 is an abundant number, since it is smaller than the sum of its proper divisors (37144748).

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

30991912 is a wasteful number, since it uses less digits than its factorization.

30991912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 650 (or 639 counting only the distinct ones).

The product of its (nonzero) digits is 4374, while the sum is 34.

The square root of 30991912 is about 5567.0379916074. The cubic root of 30991912 is about 314.1107429847.

The spelling of 30991912 in words is "thirty million, nine hundred ninety-one thousand, nine hundred twelve".