18816779520 has 720 divisors, whose sum is σ = 83979358848. Its totient is φ = 3908321280.

The previous prime is 18816779507. The next prime is 18816779587. The reversal of 18816779520 is 2597761881.

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 (54).

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, 7982182 + ... + 7984538.

Almost surely, 2^18816779520 is an apocalyptic number.

18816779520 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 18816779520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41989679424).

18816779520 is an abundant number, since it is smaller than the sum of its proper divisors (65162579328).

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

18816779520 is a wasteful number, since it uses less digits than its factorization.

18816779520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2408 (or 2385 counting only the distinct ones).

The product of its (nonzero) digits is 1693440, while the sum is 54.

The spelling of 18816779520 in words is "eighteen billion, eight hundred sixteen million, seven hundred seventy-nine thousand, five hundred twenty".