18071217 has 6 divisors (see below), whose sum is σ = 26102882. Its totient is φ = 12047472.

The previous prime is 18071177. The next prime is 18071257. The reversal of 18071217 is 71217081.

It is an interprime number because it is at equal distance from previous prime (18071177) and next prime (18071257).

It can be written as a sum of positive squares in only one way, i.e., 16573041 + 1498176 = 4071^2 + 1224^2 .

It is not a de Polignac number, because 18071217 - 2¹¹ = 18069169 is a prime.

It is a super-2 number, since 2×18071217² = 653137767722178, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18071257) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1003948 + ... + 1003965.

Almost surely, 2^18071217 is an apocalyptic number.

It is an amenable number.

18071217 is a deficient number, since it is larger than the sum of its proper divisors (8031665).

18071217 is a wasteful number, since it uses less digits than its factorization.

18071217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2007919 (or 2007916 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 27.

The square root of 18071217 is about 4251.0254057110. The cubic root of 18071217 is about 262.4193166999.

Adding to 18071217 its reverse (71217081), we get a palindrome (89288298).

The spelling of 18071217 in words is "eighteen million, seventy-one thousand, two hundred seventeen".