18038664 has 72 divisors (see below), whose sum is σ = 56842110. Its totient is φ = 5152896.

The previous prime is 18038663. The next prime is 18038677. The reversal of 18038664 is 46683081.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 17994564 + 44100 = 4242^2 + 210^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (18038663) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 972 + ... + 6084.

Almost surely, 2^18038664 is an apocalyptic number.

18038664 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18038664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28421055).

18038664 is an abundant number, since it is smaller than the sum of its proper divisors (38803446).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18038664 is a wasteful number, since it uses less digits than its factorization.

18038664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5139 (or 5125 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 18038664 is about 4247.1948389496. The cubic root of 18038664 is about 262.2616503109.

The spelling of 18038664 in words is "eighteen million, thirty-eight thousand, six hundred sixty-four".