18224638 has 4 divisors (see below), whose sum is σ = 27336960. Its totient is φ = 9112318.

The previous prime is 18224617. The next prime is 18224639. The reversal of 18224638 is 83642281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83642281 = 47 ⋅1779623.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18224639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4556158 + ... + 4556161.

It is an arithmetic number, because the mean of its divisors is an integer number (6834240).

Almost surely, 2^18224638 is an apocalyptic number.

18224638 is a deficient number, since it is larger than the sum of its proper divisors (9112322).

18224638 is an equidigital number, since it uses as much as digits as its factorization.

18224638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9112321.

The product of its digits is 18432, while the sum is 34.

The square root of 18224638 is about 4269.0324430718. The cubic root of 18224638 is about 263.1598540500.

The spelling of 18224638 in words is "eighteen million, two hundred twenty-four thousand, six hundred thirty-eight".