18008397220 has 96 divisors (see below), whose sum is σ = 43471209600. Its totient is φ = 6197529600.

The previous prime is 18008397161. The next prime is 18008397223. The reversal of 18008397220 is 2279380081.

It is not an unprimeable number, because it can be changed into a prime (18008397223) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6189126 + ... + 6192034.

It is an arithmetic number, because the mean of its divisors is an integer number (452825100).

Almost surely, 2^18008397220 is an apocalyptic number.

18008397220 is a gapful number since it is divisible by the number (10) 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 18008397220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21735604800).

18008397220 is an abundant number, since it is smaller than the sum of its proper divisors (25462812380).

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

18008397220 is a wasteful number, since it uses less digits than its factorization.

18008397220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4429 (or 4427 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 40.

The spelling of 18008397220 in words is "eighteen billion, eight million, three hundred ninety-seven thousand, two hundred twenty".