180516721 has 16 divisors (see below), whose sum is σ = 225360000. Its totient is φ = 140474880.

The previous prime is 180516703. The next prime is 180516731. The reversal of 180516721 is 127615081.

180516721 = 4046² + 4047² + ... + 4056².

It is not a de Polignac number, because 180516721 - 2⁹ = 180516209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (180516731) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 95235 + ... + 97111.

It is an arithmetic number, because the mean of its divisors is an integer number (14085000).

Almost surely, 2^180516721 is an apocalyptic number.

180516721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

180516721 is a deficient number, since it is larger than the sum of its proper divisors (44843279).

180516721 is a wasteful number, since it uses less digits than its factorization.

180516721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3144.

The product of its (nonzero) digits is 3360, while the sum is 31.

The square root of 180516721 is about 13435.6511193168. The cubic root of 180516721 is about 565.1613823591.

The spelling of 180516721 in words is "one hundred eighty million, five hundred sixteen thousand, seven hundred twenty-one".