18280705 has 4 divisors (see below), whose sum is σ = 21936852. Its totient is φ = 14624560.

The previous prime is 18280693. The next prime is 18280709. The reversal of 18280705 is 50708281.

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 4210704 + 14070001 = 2052^2 + 3751^2 .

It is not a de Polignac number, because 18280705 - 2⁵ = 18280673 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18280709) 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, 1828066 + ... + 1828075.

It is an arithmetic number, because the mean of its divisors is an integer number (5484213).

Almost surely, 2^18280705 is an apocalyptic number.

It is an amenable number.

18280705 is a deficient number, since it is larger than the sum of its proper divisors (3656147).

18280705 is an equidigital number, since it uses as much as digits as its factorization.

18280705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3656146.

The product of its (nonzero) digits is 4480, while the sum is 31.

The square root of 18280705 is about 4275.5941107640. The cubic root of 18280705 is about 263.4294429222.

Adding to 18280705 its reverse (50708281), we get a palindrome (68988986).

The spelling of 18280705 in words is "eighteen million, two hundred eighty thousand, seven hundred five".