18997312320 has 672 divisors, whose sum is σ = 82038797568. Its totient is φ = 4084826112.

The previous prime is 18997312267. The next prime is 18997312339. The reversal of 18997312320 is 2321379981.

18997312320 is a `hidden beast` number, since 1 + 8 + 9 + 9 + 7 + 312 + 320 = 666.

It is a tau number, because it is divible by the number of its divisors (672).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 9252414 + ... + 9254466.

It is an arithmetic number, because the mean of its divisors is an integer number (122081544).

Almost surely, 2^18997312320 is an apocalyptic number.

18997312320 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 18997312320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41019398784).

18997312320 is an abundant number, since it is smaller than the sum of its proper divisors (63041485248).

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

18997312320 is a wasteful number, since it uses less digits than its factorization.

18997312320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2109 (or 2087 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 45.

The spelling of 18997312320 in words is "eighteen billion, nine hundred ninety-seven million, three hundred twelve thousand, three hundred twenty".