18168074521 has 3 divisors (see below), whose sum is σ = 18168209311. Its totient is φ = 18167939732.

The previous prime is 18168074501. The next prime is 18168074537. The reversal of 18168074521 is 12547086181.

The square root of 18168074521 is 134789.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 18114198921 + 53875600 = 134589^2 + 7340^2 .

It is not a de Polignac number, because 18168074521 - 2⁹ = 18168074009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18168074501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 67395 + ... + 202183.

Almost surely, 2^18168074521 is an apocalyptic number.

18168074521 is the 134789-th square number.

18168074521 is the 67395-th centered octagonal number.

It is an amenable number.

18168074521 is a deficient number, since it is larger than the sum of its proper divisors (134790).

18168074521 is an frugal number, since it uses more digits than its factorization.

18168074521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 269578 (or 134789 counting only the distinct ones).

The product of its (nonzero) digits is 107520, while the sum is 43.

The spelling of 18168074521 in words is "eighteen billion, one hundred sixty-eight million, seventy-four thousand, five hundred twenty-one".