18555920 has 40 divisors (see below), whose sum is σ = 43437696. Its totient is φ = 7371648.

The previous prime is 18555899. The next prime is 18555923. The reversal of 18555920 is 2955581.

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (18555923) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12329 + ... + 13751.

Almost surely, 2^18555920 is an apocalyptic number.

18555920 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 18555920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21718848).

18555920 is an abundant number, since it is smaller than the sum of its proper divisors (24881776).

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

18555920 is a wasteful number, since it uses less digits than its factorization.

18555920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1599 (or 1593 counting only the distinct ones).

The product of its (nonzero) digits is 18000, while the sum is 35.

The square root of 18555920 is about 4307.6582965690. The cubic root of 18555920 is about 264.7448356715.

The spelling of 18555920 in words is "eighteen million, five hundred fifty-five thousand, nine hundred twenty".