18180323017921 has 9 divisors (see below), whose sum is σ = 18483511402083. Its totient is φ = 17882029105320.

The previous prime is 18180323017891. The next prime is 18180323017939. The reversal of 18180323017921 is 12971032308181.

The square root of 18180323017921 is 4263839.

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., 591190294321 + 17589132723600 = 768889^2 + 4193940^2 .

It is not a de Polignac number, because 18180323017921 - 2⁴³ = 9384229995713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18180323017421) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 260059230 + ... + 260129128.

Almost surely, 2^{18180323017921} is an apocalyptic number.

18180323017921 is the 4263839-th square number.

18180323017921 is the 2131920-th centered octagonal number.

It is an amenable number.

18180323017921 is a deficient number, since it is larger than the sum of its proper divisors (303188384162).

18180323017921 is an frugal number, since it uses more digits than its factorization.

18180323017921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139920 (or 69960 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 46.

The spelling of 18180323017921 in words is "eighteen trillion, one hundred eighty billion, three hundred twenty-three million, seventeen thousand, nine hundred twenty-one".