30921320 has 32 divisors (see below), whose sum is σ = 70198920. Its totient is φ = 12257280.

The previous prime is 30921301. The next prime is 30921383. The reversal of 30921320 is 2312903.

It can be written as a sum of positive squares in 4 ways, for example, as 19483396 + 11437924 = 4414^2 + 3382^2 .

It is a super-2 number, since 2×30921320² = 1912256061084800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 30921292 and 30921301.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1100 + ... + 7940.

Almost surely, 2^30921320 is an apocalyptic number.

It is an amenable number.

30921320 is an abundant number, since it is smaller than the sum of its proper divisors (39277600).

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

30921320 is a wasteful number, since it uses less digits than its factorization.

30921320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6965 (or 6961 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 20.

The square root of 30921320 is about 5560.6942012666. The cubic root of 30921320 is about 313.8720725176.

The spelling of 30921320 in words is "thirty million, nine hundred twenty-one thousand, three hundred twenty".