18399870 has 24 divisors (see below), whose sum is σ = 47839896. Its totient is φ = 4906608.

The previous prime is 18399859. The next prime is 18399883. The reversal of 18399870 is 7899381.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

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, 102132 + ... + 102311.

It is an arithmetic number, because the mean of its divisors is an integer number (1993329).

Almost surely, 2^18399870 is an apocalyptic number.

18399870 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18399870 is an abundant number, since it is smaller than the sum of its proper divisors (29440026).

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

18399870 is a wasteful number, since it uses less digits than its factorization.

18399870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 204456 (or 204453 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The square root of 18399870 is about 4289.5069646755. The cubic root of 18399870 is about 264.0006026157. Note that the first 3 decimals are identical.

The spelling of 18399870 in words is "eighteen million, three hundred ninety-nine thousand, eight hundred seventy".