18219981600 has 216 divisors, whose sum is σ = 67630202640. Its totient is φ = 4602908160.

The previous prime is 18219981587. The next prime is 18219981623. The reversal of 18219981600 is 618991281.

18219981600 is a `hidden beast` number, since 18 + 21 + 9 + 9 + 8 + 1 + 600 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 70207 + ... + 203393.

It is an arithmetic number, because the mean of its divisors is an integer number (313102790).

Almost surely, 2^18219981600 is an apocalyptic number.

18219981600 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 18219981600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33815101320).

18219981600 is an abundant number, since it is smaller than the sum of its proper divisors (49410221040).

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

18219981600 is a wasteful number, since it uses less digits than its factorization.

18219981600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133232 (or 133216 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 45.

The spelling of 18219981600 in words is "eighteen billion, two hundred nineteen million, nine hundred eighty-one thousand, six hundred".