18689197 has 2 divisors, whose sum is σ = 18689198. Its totient is φ = 18689196.

The previous prime is 18689191. The next prime is 18689213. The reversal of 18689197 is 79198681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17816841 + 872356 = 4221^2 + 934^2 .

It is a cyclic number.

It is not a de Polignac number, because 18689197 - 2³ = 18689189 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18689197.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18689191) 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, 9344598 + 9344599.

It is an arithmetic number, because the mean of its divisors is an integer number (9344599).

Almost surely, 2^18689197 is an apocalyptic number.

It is an amenable number.

18689197 is a deficient number, since it is larger than the sum of its proper divisors (1).

18689197 is an equidigital number, since it uses as much as digits as its factorization.

18689197 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 217728, while the sum is 49.

The square root of 18689197 is about 4323.1003920797. The cubic root of 18689197 is about 265.3771631942.

The spelling of 18689197 in words is "eighteen million, six hundred eighty-nine thousand, one hundred ninety-seven".