18511009920 has 512 divisors, whose sum is σ = 74335968000. Its totient is φ = 4315742208.

The previous prime is 18511009897. The next prime is 18511009961. The reversal of 18511009920 is 2990011581.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4265992 + ... + 4270328.

Almost surely, 2^18511009920 is an apocalyptic number.

18511009920 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 18511009920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37167984000).

18511009920 is an abundant number, since it is smaller than the sum of its proper divisors (55824958080).

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

18511009920 is a wasteful number, since it uses less digits than its factorization.

18511009920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4397 (or 4379 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 36.

The spelling of 18511009920 in words is "eighteen billion, five hundred eleven million, nine thousand, nine hundred twenty".