30721280 has 36 divisors (see below), whose sum is σ = 73590132. Its totient is φ = 12288000.

The previous prime is 30721277. The next prime is 30721333. The reversal of 30721280 is 8212703.

It can be written as a sum of positive squares in 2 ways, for example, as 9634816 + 21086464 = 3104^2 + 4592^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10721 + ... + 13280.

Almost surely, 2^30721280 is an apocalyptic number.

It is an amenable number.

30721280 is an abundant number, since it is smaller than the sum of its proper divisors (42868852).

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

30721280 is an equidigital number, since it uses as much as digits as its factorization.

30721280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24022 (or 24008 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 30721280 is about 5542.6780530715. The cubic root of 30721280 is about 313.1937610860.

Adding to 30721280 its reverse (8212703), we get a palindrome (38933983).

The spelling of 30721280 in words is "thirty million, seven hundred twenty-one thousand, two hundred eighty".