18617904633409 has 9 divisors (see below), whose sum is σ = 18939069742243. Its totient is φ = 18302096666632.

The previous prime is 18617904633403. The next prime is 18617904633421. The reversal of 18617904633409 is 90433640971681.

The square root of 18617904633409 is 4314847.

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., 14327322671025 + 4290581962384 = 3785145^2 + 2071372^2 .

It is not a de Polignac number, because 18617904633409 - 2²¹ = 18617902536257 is a prime.

It is a super-2 number, since 2×18617904633409² (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 (18617904633403) 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, 254539407 + ... + 254612539.

Almost surely, 2^{18617904633409} is an apocalyptic number.

18617904633409 is the 4314847-th square number.

18617904633409 is the 2157424-th centered octagonal number.

It is an amenable number.

18617904633409 is a deficient number, since it is larger than the sum of its proper divisors (321165108834).

18617904633409 is an frugal number, since it uses more digits than its factorization.

18617904633409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146384 (or 73192 counting only the distinct ones).

The product of its (nonzero) digits is 23514624, while the sum is 61.

The spelling of 18617904633409 in words is "eighteen trillion, six hundred seventeen billion, nine hundred four million, six hundred thirty-three thousand, four hundred nine".