18321899328 has 560 divisors, whose sum is σ = 60941833920. Its totient is φ = 5415911424.

The previous prime is 18321899287. The next prime is 18321899333. The reversal of 18321899328 is 82399812381.

18321899328 is a `hidden beast` number, since 18 + 3 + 218 + 99 + 328 = 666.

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

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 171232651 + ... + 171232757.

Almost surely, 2^18321899328 is an apocalyptic number.

18321899328 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 18321899328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30470916960).

18321899328 is an abundant number, since it is smaller than the sum of its proper divisors (42619934592).

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

18321899328 is a wasteful number, since it uses less digits than its factorization.

18321899328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244 (or 225 counting only the distinct ones).

The product of its digits is 1492992, while the sum is 54.

The spelling of 18321899328 in words is "eighteen billion, three hundred twenty-one million, eight hundred ninety-nine thousand, three hundred twenty-eight".