18113204033521 has 9 divisors (see below), whose sum is σ = 18146328975201. Its totient is φ = 18080139472512.

The previous prime is 18113204033513. The next prime is 18113204033531. The reversal of 18113204033521 is 12533040231181.

The square root of 18113204033521 is 4255961.

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

It can be written as a sum of positive squares in 4 ways, for example, as 6475554073521 + 11637649960000 = 2544711^2 + 3411400^2 .

It is not a de Polignac number, because 18113204033521 - 2³ = 18113204033513 is a prime.

It is a super-2 number, since 2×18113204033521² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18113204033531) 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, 2523781285 + ... + 2523788461.

Almost surely, 2^{18113204033521} is an apocalyptic number.

18113204033521 is the 4255961-st square number.

18113204033521 is the 2127981-st centered octagonal number.

It is an amenable number.

18113204033521 is a deficient number, since it is larger than the sum of its proper divisors (33124941680).

18113204033521 is an frugal number, since it uses more digits than its factorization.

18113204033521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15540 (or 7770 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 34.

The spelling of 18113204033521 in words is "eighteen trillion, one hundred thirteen billion, two hundred four million, thirty-three thousand, five hundred twenty-one".