30921472 has 54 divisors (see below), whose sum is σ = 64371692. Its totient is φ = 14816256.

The previous prime is 30921467. The next prime is 30921479. The reversal of 30921472 is 27412903.

It is a super-2 number, since 2×30921472² = 1912274861293568, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a self number, because there is not a number n which added to its sum of digits gives 30921472.

It is not an unprimeable number, because it can be changed into a prime (30921479) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 583398 + ... + 583450.

Almost surely, 2^30921472 is an apocalyptic number.

30921472 is a gapful number since it is divisible by the number (32) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 30921472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32185846).

30921472 is an abundant number, since it is smaller than the sum of its proper divisors (33450220).

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

30921472 is an frugal number, since it uses more digits than its factorization.

30921472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165 (or 98 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 30921472 is about 5560.7078686081. The cubic root of 30921472 is about 313.8725868173.

The spelling of 30921472 in words is "thirty million, nine hundred twenty-one thousand, four hundred seventy-two".