18008643 has 4 divisors (see below), whose sum is σ = 24011528. Its totient is φ = 12005760.

The previous prime is 18008633. The next prime is 18008647. The reversal of 18008643 is 34680081.

It is a happy number.

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

It is not a de Polignac number, because 18008643 - 2⁶ = 18008579 is a prime.

It is a super-2 number, since 2×18008643² = 648622445402898, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18008643.

It is not an unprimeable number, because it can be changed into a prime (18008647) 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, 3001438 + ... + 3001443.

It is an arithmetic number, because the mean of its divisors is an integer number (6002882).

Almost surely, 2^18008643 is an apocalyptic number.

18008643 is a deficient number, since it is larger than the sum of its proper divisors (6002885).

18008643 is an equidigital number, since it uses as much as digits as its factorization.

18008643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6002884.

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 18008643 is about 4243.6591521940. The cubic root of 18008643 is about 262.1160791309.

The spelling of 18008643 in words is "eighteen million, eight thousand, six hundred forty-three".