30971920 has 60 divisors (see below), whose sum is σ = 83777004. Its totient is φ = 10617600.

The previous prime is 30971917. The next prime is 30971951. The reversal of 30971920 is 2917903.

It can be written as a sum of positive squares in 2 ways, for example, as 16257024 + 14714896 = 4032^2 + 3836^2 .

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 31 + ... + 7870.

It is a vampire number, since it can be written as 3920 ⋅ 7901 (with its own digits).

Almost surely, 2^30971920 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 30971920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41888502).

30971920 is an abundant number, since it is smaller than the sum of its proper divisors (52805084).

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

30971920 is a wasteful number, since it uses less digits than its factorization.

30971920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7928 (or 7915 counting only the distinct ones).

The product of its (nonzero) digits is 3402, while the sum is 31.

The square root of 30971920 is about 5565.2421330972. The cubic root of 30971920 is about 314.0431871576.

The spelling of 30971920 in words is "thirty million, nine hundred seventy-one thousand, nine hundred twenty".