18409777920 has 432 divisors, whose sum is σ = 67519452000. Its totient is φ = 4618321920.

The previous prime is 18409777913. The next prime is 18409777927. The reversal of 18409777920 is 2977790481.

It is an interprime number because it is at equal distance from previous prime (18409777913) and next prime (18409777927).

It is not an unprimeable number, because it can be changed into a prime (18409777927) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 52749906 + ... + 52750254.

Almost surely, 2^18409777920 is an apocalyptic number.

18409777920 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 18409777920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33759726000).

18409777920 is an abundant number, since it is smaller than the sum of its proper divisors (49109674080).

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

18409777920 is a wasteful number, since it uses less digits than its factorization.

18409777920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 636 (or 619 counting only the distinct ones).

The product of its (nonzero) digits is 1778112, while the sum is 54.

The spelling of 18409777920 in words is "eighteen billion, four hundred nine million, seven hundred seventy-seven thousand, nine hundred twenty".