18221265 has 24 divisors (see below), whose sum is σ = 32123520. Its totient is φ = 9551904.

The previous prime is 18221257. The next prime is 18221339. The reversal of 18221265 is 56212281.

It is a happy number.

It is not a de Polignac number, because 18221265 - 2³ = 18221257 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 777 + ... + 6086.

It is an arithmetic number, because the mean of its divisors is an integer number (1338480).

Almost surely, 2^18221265 is an apocalyptic number.

18221265 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18221265 is a deficient number, since it is larger than the sum of its proper divisors (13902255).

18221265 is a wasteful number, since it uses less digits than its factorization.

18221265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6933 (or 6930 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The square root of 18221265 is about 4268.6373704029. The cubic root of 18221265 is about 263.1436179167.

The spelling of 18221265 in words is "eighteen million, two hundred twenty-one thousand, two hundred sixty-five".