18390859 has 4 divisors (see below), whose sum is σ = 18472104. Its totient is φ = 18309616.

The previous prime is 18390857. The next prime is 18390877. The reversal of 18390859 is 95809381.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 95809381 = 19 ⋅5042599.

It is a cyclic number.

It is not a de Polignac number, because 18390859 - 2¹ = 18390857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18390851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40282 + ... + 40735.

It is an arithmetic number, because the mean of its divisors is an integer number (4618026).

Almost surely, 2^18390859 is an apocalyptic number.

18390859 is a deficient number, since it is larger than the sum of its proper divisors (81245).

18390859 is an equidigital number, since it uses as much as digits as its factorization.

18390859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81244.

The product of its (nonzero) digits is 77760, while the sum is 43.

The square root of 18390859 is about 4288.4564822323. The cubic root of 18390859 is about 263.9574990887.

The spelling of 18390859 in words is "eighteen million, three hundred ninety thousand, eight hundred fifty-nine".