18509868 has 36 divisors (see below), whose sum is σ = 50389248. Its totient is φ = 5695200.

The previous prime is 18509849. The next prime is 18509873. The reversal of 18509868 is 86890581.

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, 19308 + ... + 20243.

Almost surely, 2^18509868 is an apocalyptic number.

18509868 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

18509868 is an abundant number, since it is smaller than the sum of its proper divisors (31879380).

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

18509868 is a wasteful number, since it uses less digits than its factorization.

18509868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39574 (or 39569 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 45.

The square root of 18509868 is about 4302.3096122897. The cubic root of 18509868 is about 264.5256400519.

The spelling of 18509868 in words is "eighteen million, five hundred nine thousand, eight hundred sixty-eight".