18405005 has 4 divisors (see below), whose sum is σ = 22086012. Its totient is φ = 14724000.

The previous prime is 18404987. The next prime is 18405007. The reversal of 18405005 is 50050481.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9320809 + 9084196 = 3053^2 + 3014^2 .

It is not a de Polignac number, because 18405005 - 2¹² = 18400909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18405007) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1840496 + ... + 1840505.

It is an arithmetic number, because the mean of its divisors is an integer number (5521503).

Almost surely, 2^18405005 is an apocalyptic number.

It is an amenable number.

18405005 is a deficient number, since it is larger than the sum of its proper divisors (3681007).

18405005 is an equidigital number, since it uses as much as digits as its factorization.

18405005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3681006.

The product of its (nonzero) digits is 800, while the sum is 23.

The square root of 18405005 is about 4290.1054765588. The cubic root of 18405005 is about 264.0251592567.

Adding to 18405005 its reverse (50050481), we get a palindrome (68455486).

The spelling of 18405005 in words is "eighteen million, four hundred five thousand, five".