18280305 has 24 divisors (see below), whose sum is σ = 31824000. Its totient is φ = 9707040.

The previous prime is 18280303. The next prime is 18280309. The reversal of 18280305 is 50308281.

It is a happy number.

It is not a de Polignac number, because 18280305 - 2¹ = 18280303 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18280303) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11446 + ... + 12944.

It is an arithmetic number, because the mean of its divisors is an integer number (1326000).

Almost surely, 2^18280305 is an apocalyptic number.

18280305 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18280305 is a deficient number, since it is larger than the sum of its proper divisors (13543695).

18280305 is a wasteful number, since it uses less digits than its factorization.

18280305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1781 (or 1778 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 18280305 is about 4275.5473333832. The cubic root of 18280305 is about 263.4275215421.

Adding to 18280305 its reverse (50308281), we get a palindrome (68588586).

The spelling of 18280305 in words is "eighteen million, two hundred eighty thousand, three hundred five".