18218617 has 2 divisors, whose sum is σ = 18218618. Its totient is φ = 18218616.

The previous prime is 18218597. The next prime is 18218639. The reversal of 18218617 is 71681281.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16289296 + 1929321 = 4036^2 + 1389^2 .

It is a cyclic number.

It is not a de Polignac number, because 18218617 - 2⁷ = 18218489 is a prime.

It is a super-4 number, since 4×18218617⁴ (a number of 30 digits) contains 4444 as substring. Note that it is a super-d number also for d = 3.

It is not a weakly prime, because it can be changed into another prime (18212617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9109308 + 9109309.

It is an arithmetic number, because the mean of its divisors is an integer number (9109309).

Almost surely, 2^18218617 is an apocalyptic number.

It is an amenable number.

18218617 is a deficient number, since it is larger than the sum of its proper divisors (1).

18218617 is an equidigital number, since it uses as much as digits as its factorization.

18218617 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5376, while the sum is 34.

The square root of 18218617 is about 4268.3271898954. The cubic root of 18218617 is about 263.1308702094.

Adding to 18218617 its reverse (71681281), we get a palindrome (89899898).

The spelling of 18218617 in words is "eighteen million, two hundred eighteen thousand, six hundred seventeen".