18553116817 has 4 divisors (see below), whose sum is σ = 18560128576. Its totient is φ = 18546105060.

The previous prime is 18553116739. The next prime is 18553116833. The reversal of 18553116817 is 71861135581.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 71861135581 = 69779 ⋅1029839.

It is a cyclic number.

It is not a de Polignac number, because 18553116817 - 2⁷ = 18553116689 is a prime.

It is a super-2 number, since 2×18553116817² (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 (18553116917) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3501909 + ... + 3507202.

It is an arithmetic number, because the mean of its divisors is an integer number (4640032144).

Almost surely, 2^18553116817 is an apocalyptic number.

It is an amenable number.

18553116817 is a deficient number, since it is larger than the sum of its proper divisors (7011759).

18553116817 is an equidigital number, since it uses as much as digits as its factorization.

18553116817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7011758.

The product of its digits is 201600, while the sum is 46.

The spelling of 18553116817 in words is "eighteen billion, five hundred fifty-three million, one hundred sixteen thousand, eight hundred seventeen".