18921265 has 16 divisors (see below), whose sum is σ = 25240896. Its totient is φ = 13499200.

The previous prime is 18921263. The next prime is 18921271. The reversal of 18921265 is 56212981.

It is not a de Polignac number, because 18921265 - 2¹ = 18921263 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 18921265.

It is not an unprimeable number, because it can be changed into a prime (18921263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 331 + ... + 6160.

It is an arithmetic number, because the mean of its divisors is an integer number (1577556).

Almost surely, 2^18921265 is an apocalyptic number.

It is an amenable number.

18921265 is a deficient number, since it is larger than the sum of its proper divisors (6319631).

18921265 is a wasteful number, since it uses less digits than its factorization.

18921265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6560.

The product of its digits is 8640, while the sum is 34.

The square root of 18921265 is about 4349.8580436607. The cubic root of 18921265 is about 266.4710640239.

The spelling of 18921265 in words is "eighteen million, nine hundred twenty-one thousand, two hundred sixty-five".