18072217 has 4 divisors (see below), whose sum is σ = 18104116. Its totient is φ = 18040320.

The previous prime is 18072209. The next prime is 18072247. The reversal of 18072217 is 71227081.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71227081 = 1019 ⋅69899.

It can be written as a sum of positive squares in 2 ways, for example, as 15178816 + 2893401 = 3896^2 + 1701^2 .

It is a cyclic number.

It is not a de Polignac number, because 18072217 - 2³ = 18072209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18072247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15084 + ... + 16237.

It is an arithmetic number, because the mean of its divisors is an integer number (4526029).

Almost surely, 2^18072217 is an apocalyptic number.

It is an amenable number.

18072217 is a deficient number, since it is larger than the sum of its proper divisors (31899).

18072217 is an equidigital number, since it uses as much as digits as its factorization.

18072217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31898.

The product of its (nonzero) digits is 1568, while the sum is 28.

The square root of 18072217 is about 4251.1430227646. The cubic root of 18072217 is about 262.4241570763.

Adding to 18072217 its reverse (71227081), we get a palindrome (89299298).

The spelling of 18072217 in words is "eighteen million, seventy-two thousand, two hundred seventeen".