18008644 has 24 divisors (see below), whose sum is σ = 34449408. Its totient is φ = 8200320.

The previous prime is 18008633. The next prime is 18008647. The reversal of 18008644 is 44680081.

It is a super-2 number, since 2×18008644² = 648622517437472, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (31).

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 7 ways as a sum of consecutive naturals, for example, 2164 + ... + 6379.

It is an arithmetic number, because the mean of its divisors is an integer number (1435392).

Almost surely, 2^18008644 is an apocalyptic number.

It is an amenable number.

18008644 is a deficient number, since it is larger than the sum of its proper divisors (16440764).

18008644 is a wasteful number, since it uses less digits than its factorization.

18008644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8595 (or 8593 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 31.

The square root of 18008644 is about 4243.6592700169. The cubic root of 18008644 is about 262.1160839826.

The spelling of 18008644 in words is "eighteen million, eight thousand, six hundred forty-four".