16304480721 has 27 divisors (see below), whose sum is σ = 24352867227. Its totient is φ = 10511358480.

The previous prime is 16304480711. The next prime is 16304480749. The reversal of 16304480721 is 12708440361.

The square root of 16304480721 is 127689.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 16115033025 + 189447696 = 126945^2 + 13764^2 .

It is not a de Polignac number, because 16304480721 - 2⁷ = 16304480593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16304480711) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 11874391 + ... + 11875763.

Almost surely, 2^16304480721 is an apocalyptic number.

16304480721 is the 127689-th square number.

16304480721 is the 63845-th centered octagonal number.

It is an amenable number.

16304480721 is a deficient number, since it is larger than the sum of its proper divisors (8048386506).

16304480721 is an frugal number, since it uses more digits than its factorization.

16304480721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2814 (or 1407 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

Multiplying 16304480721 by its sum of digits (36), we get a square (586961305956 = 766134²).

It can be divided in two parts, 16304 and 480721, that added together give a square (497025 = 705²).

The spelling of 16304480721 in words is "sixteen billion, three hundred four million, four hundred eighty thousand, seven hundred twenty-one".