18405540 has 36 divisors (see below), whose sum is σ = 55830684. Its totient is φ = 4908096.

The previous prime is 18405511. The next prime is 18405551. The reversal of 18405540 is 4550481.

It can be written as a sum of positive squares in 2 ways, for example, as 12616704 + 5788836 = 3552^2 + 2406^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 50947 + ... + 51306.

Almost surely, 2^18405540 is an apocalyptic number.

18405540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18405540 is an abundant number, since it is smaller than the sum of its proper divisors (37425144).

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

18405540 is a wasteful number, since it uses less digits than its factorization.

18405540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102268 (or 102263 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

The square root of 18405540 is about 4290.1678288850. The cubic root of 18405540 is about 264.0277174755.

The spelling of 18405540 in words is "eighteen million, four hundred five thousand, five hundred forty".