18115665 has 16 divisors (see below), whose sum is σ = 29533248. Its totient is φ = 9478976.

The previous prime is 18115639. The next prime is 18115667. The reversal of 18115665 is 56651181.

18115665 is nontrivially palindromic in base 2.

It is a cyclic number.

It is not a de Polignac number, because 18115665 - 2¹⁰ = 18114641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18115667) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10599 + ... + 12188.

It is an arithmetic number, because the mean of its divisors is an integer number (1845828).

Almost surely, 2^18115665 is an apocalyptic number.

18115665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18115665 is a deficient number, since it is larger than the sum of its proper divisors (11417583).

18115665 is a wasteful number, since it uses less digits than its factorization.

18115665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22848.

The product of its digits is 7200, while the sum is 33.

The square root of 18115665 is about 4256.2501101322. The cubic root of 18115665 is about 262.6342895652.

The spelling of 18115665 in words is "eighteen million, one hundred fifteen thousand, six hundred sixty-five".