18918617 has 2 divisors, whose sum is σ = 18918618. Its totient is φ = 18918616.

The previous prime is 18918593. The next prime is 18918619. The reversal of 18918617 is 71681981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16032016 + 2886601 = 4004^2 + 1699^2 .

It is a cyclic number.

It is not a de Polignac number, because 18918617 - 2¹² = 18914521 is a prime.

It is a super-3 number, since 3×18918617³ (a number of 23 digits) contains 333 as substring.

Together with 18918619, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18918619) 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 as a sum of consecutive naturals, namely, 9459308 + 9459309.

It is an arithmetic number, because the mean of its divisors is an integer number (9459309).

Almost surely, 2^18918617 is an apocalyptic number.

It is an amenable number.

18918617 is a deficient number, since it is larger than the sum of its proper divisors (1).

18918617 is an equidigital number, since it uses as much as digits as its factorization.

18918617 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24192, while the sum is 41.

The square root of 18918617 is about 4349.5536552617. The cubic root of 18918617 is about 266.4586327145.

The spelling of 18918617 in words is "eighteen million, nine hundred eighteen thousand, six hundred seventeen".