18038665 has 12 divisors (see below), whose sum is σ = 21979404. Its totient is φ = 14212224.

The previous prime is 18038663. The next prime is 18038677. The reversal of 18038665 is 56683081.

It can be written as a sum of positive squares in 6 ways, for example, as 2134521 + 15904144 = 1461^2 + 3988^2 .

It is not a de Polignac number, because 18038665 - 2¹ = 18038663 is a prime.

It is a Duffinian number.

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

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 26307 + ... + 26983.

It is an arithmetic number, because the mean of its divisors is an integer number (1831617).

Almost surely, 2^18038665 is an apocalyptic number.

It is an amenable number.

18038665 is a deficient number, since it is larger than the sum of its proper divisors (3940739).

18038665 is an frugal number, since it uses more digits than its factorization.

18038665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 828 (or 755 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 37.

The square root of 18038665 is about 4247.1949566743. The cubic root of 18038665 is about 262.2616551572.

The spelling of 18038665 in words is "eighteen million, thirty-eight thousand, six hundred sixty-five".