18039905 has 24 divisors (see below), whose sum is σ = 24116472. Its totient is φ = 12939264.

The previous prime is 18039883. The next prime is 18039929. The reversal of 18039905 is 50993081.

It can be written as a sum of positive squares in 12 ways, for example, as 1336336 + 16703569 = 1156^2 + 4087^2 .

It is not a de Polignac number, because 18039905 - 2¹⁴ = 18023521 is a prime.

It is a Duffinian number.

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, 30977 + ... + 31553.

It is an arithmetic number, because the mean of its divisors is an integer number (1004853).

Almost surely, 2^18039905 is an apocalyptic number.

It is an amenable number.

18039905 is a deficient number, since it is larger than the sum of its proper divisors (6076567).

18039905 is a wasteful number, since it uses less digits than its factorization.

18039905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 645 (or 632 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 35.

The square root of 18039905 is about 4247.3409328661. The cubic root of 18039905 is about 262.2676644157.

The spelling of 18039905 in words is "eighteen million, thirty-nine thousand, nine hundred five".