18509990400 has 720 divisors, whose sum is σ = 75079132128. Its totient is φ = 4478976000.

The previous prime is 18509990363. The next prime is 18509990419. The reversal of 18509990400 is 409990581.

18509990400 is a `hidden beast` number, since 18 + 509 + 9 + 90 + 40 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

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 71 ways as a sum of consecutive naturals, for example, 34214130 + ... + 34214670.

Almost surely, 2^18509990400 is an apocalyptic number.

18509990400 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 18509990400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37539566064).

18509990400 is an abundant number, since it is smaller than the sum of its proper divisors (56569141728).

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

18509990400 is an equidigital number, since it uses as much as digits as its factorization.

18509990400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 595 (or 562 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 45.

The spelling of 18509990400 in words is "eighteen billion, five hundred nine million, nine hundred ninety thousand, four hundred".