18668197 has 2 divisors, whose sum is σ = 18668198. Its totient is φ = 18668196.

The previous prime is 18668179. The next prime is 18668201. The reversal of 18668197 is 79186681.

Together with previous prime (18668179) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16597476 + 2070721 = 4074^2 + 1439^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18668197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18668297) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9334098 + 9334099.

It is an arithmetic number, because the mean of its divisors is an integer number (9334099).

Almost surely, 2^18668197 is an apocalyptic number.

It is an amenable number.

18668197 is a deficient number, since it is larger than the sum of its proper divisors (1).

18668197 is an equidigital number, since it uses as much as digits as its factorization.

18668197 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 46.

The square root of 18668197 is about 4320.6708969788. The cubic root of 18668197 is about 265.2777294758.

The spelling of 18668197 in words is "eighteen million, six hundred sixty-eight thousand, one hundred ninety-seven".