18320905 has 8 divisors (see below), whose sum is σ = 22009032. Its totient is φ = 14640768.

The previous prime is 18320899. The next prime is 18320909. The reversal of 18320905 is 50902381.

It can be written as a sum of positive squares in 4 ways, for example, as 3697929 + 14622976 = 1923^2 + 3824^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18320905 - 2⁷ = 18320777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18320909) 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 7 ways as a sum of consecutive naturals, for example, 5887 + ... + 8443.

It is an arithmetic number, because the mean of its divisors is an integer number (2751129).

Almost surely, 2^18320905 is an apocalyptic number.

It is an amenable number.

18320905 is a deficient number, since it is larger than the sum of its proper divisors (3688127).

18320905 is a wasteful number, since it uses less digits than its factorization.

18320905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3995.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 18320905 is about 4280.2926301831. The cubic root of 18320905 is about 263.6223988387.

The spelling of 18320905 in words is "eighteen million, three hundred twenty thousand, nine hundred five".