18638243 has 4 divisors (see below), whose sum is σ = 20071968. Its totient is φ = 17204520.

The previous prime is 18638227. The next prime is 18638251. The reversal of 18638243 is 34283681.

It is a happy number.

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 18638243 - 2⁴ = 18638227 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18638293) 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, 716843 + ... + 716868.

It is an arithmetic number, because the mean of its divisors is an integer number (5017992).

Almost surely, 2^18638243 is an apocalyptic number.

18638243 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

18638243 is a deficient number, since it is larger than the sum of its proper divisors (1433725).

18638243 is a wasteful number, since it uses less digits than its factorization.

18638243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1433724.

The product of its digits is 27648, while the sum is 35.

The square root of 18638243 is about 4317.2031455562. The cubic root of 18638243 is about 265.1357699911.

It can be divided in two parts, 18638 and 243, that added together give a palindrome (18881).

The spelling of 18638243 in words is "eighteen million, six hundred thirty-eight thousand, two hundred forty-three".