18863918 has 4 divisors (see below), whose sum is σ = 28295880. Its totient is φ = 9431958.

The previous prime is 18863909. The next prime is 18863951. The reversal of 18863918 is 81936881.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81936881 = 13 ⋅6302837.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4715978 + ... + 4715981.

It is an arithmetic number, because the mean of its divisors is an integer number (7073970).

Almost surely, 2^18863918 is an apocalyptic number.

18863918 is a deficient number, since it is larger than the sum of its proper divisors (9431962).

18863918 is an equidigital number, since it uses as much as digits as its factorization.

18863918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9431961.

The product of its digits is 82944, while the sum is 44.

The square root of 18863918 is about 4343.2612171040. The cubic root of 18863918 is about 266.2015827379.

The spelling of 18863918 in words is "eighteen million, eight hundred sixty-three thousand, nine hundred eighteen".