18400305 has 64 divisors (see below), whose sum is σ = 37324800. Its totient is φ = 7518720.

The previous prime is 18400301. The next prime is 18400313. The reversal of 18400305 is 50300481.

It is not a de Polignac number, because 18400305 - 2² = 18400301 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18400301) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 102706 + ... + 102884.

It is an arithmetic number, because the mean of its divisors is an integer number (583200).

Almost surely, 2^18400305 is an apocalyptic number.

18400305 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18400305 is an abundant number, since it is smaller than the sum of its proper divisors (18924495).

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

18400305 is a wasteful number, since it uses less digits than its factorization.

18400305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 294.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 18400305 is about 4289.5576695039. The cubic root of 18400305 is about 264.0026830535.

Adding to 18400305 its reverse (50300481), we get a palindrome (68700786).

The spelling of 18400305 in words is "eighteen million, four hundred thousand, three hundred five".