180724721 has 2 divisors, whose sum is σ = 180724722. Its totient is φ = 180724720.

The previous prime is 180724717. The next prime is 180724757. The reversal of 180724721 is 127427081.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 147501025 + 33223696 = 12145^2 + 5764^2 .

It is a cyclic number.

It is not a de Polignac number, because 180724721 - 2² = 180724717 is a prime.

It is a super-2 number, since 2×180724721² = 65322849561055682, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (180724711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90362360 + 90362361.

It is an arithmetic number, because the mean of its divisors is an integer number (90362361).

Almost surely, 2^180724721 is an apocalyptic number.

It is an amenable number.

180724721 is a deficient number, since it is larger than the sum of its proper divisors (1).

180724721 is an equidigital number, since it uses as much as digits as its factorization.

180724721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6272, while the sum is 32.

The square root of 180724721 is about 13443.3894907497. The cubic root of 180724721 is about 565.3783676989.

The spelling of 180724721 in words is "one hundred eighty million, seven hundred twenty-four thousand, seven hundred twenty-one".