18321665 has 16 divisors (see below), whose sum is σ = 23379840. Its totient is φ = 13735680.

The previous prime is 18321661. The next prime is 18321673. The reversal of 18321665 is 56612381.

It is a happy number.

It is not a de Polignac number, because 18321665 - 2² = 18321661 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18321661) 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, 37070 + ... + 37560.

It is an arithmetic number, because the mean of its divisors is an integer number (1461240).

Almost surely, 2^18321665 is an apocalyptic number.

It is an amenable number.

18321665 is a deficient number, since it is larger than the sum of its proper divisors (5058175).

18321665 is a wasteful number, since it uses less digits than its factorization.

18321665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 952.

The product of its digits is 8640, while the sum is 32.

The square root of 18321665 is about 4280.3814082392. The cubic root of 18321665 is about 263.6260440417.

The spelling of 18321665 in words is "eighteen million, three hundred twenty-one thousand, six hundred sixty-five".