18243217 has 4 divisors (see below), whose sum is σ = 18258660. Its totient is φ = 18227776.

The previous prime is 18243161. The next prime is 18243241. The reversal of 18243217 is 71234281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71234281 = 47 ⋅1515623.

It can be written as a sum of positive squares in 2 ways, for example, as 11082241 + 7160976 = 3329^2 + 2676^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18243217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18243517) 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, 5788 + ... + 8365.

It is an arithmetic number, because the mean of its divisors is an integer number (4564665).

Almost surely, 2^18243217 is an apocalyptic number.

It is an amenable number.

18243217 is a deficient number, since it is larger than the sum of its proper divisors (15443).

18243217 is a wasteful number, since it uses less digits than its factorization.

18243217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15442.

The product of its digits is 2688, while the sum is 28.

The square root of 18243217 is about 4271.2079087771. The cubic root of 18243217 is about 263.2492492674.

Adding to 18243217 its reverse (71234281), we get a palindrome (89477498).

It can be divided in two parts, 1824 and 3217, that added together give a square (5041 = 71²).

The spelling of 18243217 in words is "eighteen million, two hundred forty-three thousand, two hundred seventeen".