18855839 has 4 divisors (see below), whose sum is σ = 19965024. Its totient is φ = 17746656.

The previous prime is 18855821. The next prime is 18855841. The reversal of 18855839 is 93855881.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18855839 - 2²⁰ = 17807263 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18855793 and 18855802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18855899) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 554567 + ... + 554600.

It is an arithmetic number, because the mean of its divisors is an integer number (4991256).

Almost surely, 2^18855839 is an apocalyptic number.

18855839 is a deficient number, since it is larger than the sum of its proper divisors (1109185).

18855839 is a wasteful number, since it uses less digits than its factorization.

18855839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1109184.

The product of its digits is 345600, while the sum is 47.

The square root of 18855839 is about 4342.3310560113. The cubic root of 18855839 is about 266.1635745559.

The spelling of 18855839 in words is "eighteen million, eight hundred fifty-five thousand, eight hundred thirty-nine".