18738598321 has 3 divisors (see below), whose sum is σ = 18738735211. Its totient is φ = 18738461432.

The previous prime is 18738598289. The next prime is 18738598331. The reversal of 18738598321 is 12389583781.

The square root of 18738598321 is 136889.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12389583781 = 149 ⋅83151569.

It can be written as a sum of positive squares in only one way, i.e., 2791959921 + 15946638400 = 52839^2 + 126280^2 .

It is not a de Polignac number, because 18738598321 - 2⁵ = 18738598289 is a prime.

It is a super-2 number, since 2×18738598321² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18738598331) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 68445 + ... + 205333.

Almost surely, 2^18738598321 is an apocalyptic number.

18738598321 is the 136889-th square number.

18738598321 is the 68445-th centered octagonal number.

It is an amenable number.

18738598321 is a deficient number, since it is larger than the sum of its proper divisors (136890).

18738598321 is an frugal number, since it uses more digits than its factorization.

18738598321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273778 (or 136889 counting only the distinct ones).

The product of its digits is 2903040, while the sum is 55.

The spelling of 18738598321 in words is "eighteen billion, seven hundred thirty-eight million, five hundred ninety-eight thousand, three hundred twenty-one".