18117299808 has 240 divisors, whose sum is σ = 54891454464. Its totient is φ = 5859060480.

The previous prime is 18117299807. The next prime is 18117299819. The reversal of 18117299808 is 80899271181.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18117299803) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 15471063 + ... + 15472233.

Almost surely, 2^18117299808 is an apocalyptic number.

18117299808 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18117299808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27445727232).

18117299808 is an abundant number, since it is smaller than the sum of its proper divisors (36774154656).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18117299808 is a wasteful number, since it uses less digits than its factorization.

18117299808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1367 (or 1350 counting only the distinct ones).

The product of its (nonzero) digits is 580608, while the sum is 54.

The spelling of 18117299808 in words is "eighteen billion, one hundred seventeen million, two hundred ninety-nine thousand, eight hundred eight".