18125665 has 4 divisors (see below), whose sum is σ = 21750804. Its totient is φ = 14500528.

The previous prime is 18125659. The next prime is 18125687. The reversal of 18125665 is 56652181.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56652181 = 4561 ⋅12421.

It can be written as a sum of positive squares in 2 ways, for example, as 10291264 + 7834401 = 3208^2 + 2799^2 .

It is a cyclic number.

It is not a de Polignac number, because 18125665 - 2¹¹ = 18123617 is a prime.

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 18125665.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1812562 + ... + 1812571.

It is an arithmetic number, because the mean of its divisors is an integer number (5437701).

Almost surely, 2^18125665 is an apocalyptic number.

It is an amenable number.

18125665 is a deficient number, since it is larger than the sum of its proper divisors (3625139).

18125665 is an equidigital number, since it uses as much as digits as its factorization.

18125665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3625138.

The product of its digits is 14400, while the sum is 34.

The square root of 18125665 is about 4257.4246910544. The cubic root of 18125665 is about 262.6826061241.

The spelling of 18125665 in words is "eighteen million, one hundred twenty-five thousand, six hundred sixty-five".