18005720 has 32 divisors (see below), whose sum is σ = 42897600. Its totient is φ = 6778368.

The previous prime is 18005707. The next prime is 18005731. The reversal of 18005720 is 2750081.

It is a plaindrome in base 14.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12560 + ... + 13919.

It is an arithmetic number, because the mean of its divisors is an integer number (1340550).

Almost surely, 2^18005720 is an apocalyptic number.

18005720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18005720 is an abundant number, since it is smaller than the sum of its proper divisors (24891880).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18005720 is a wasteful number, since it uses less digits than its factorization.

18005720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26507 (or 26503 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 23.

The square root of 18005720 is about 4243.3147420384. The cubic root of 18005720 is about 262.1018969267.

The spelling of 18005720 in words is "eighteen million, five thousand, seven hundred twenty".