18681197 has 2 divisors, whose sum is σ = 18681198. Its totient is φ = 18681196.

The previous prime is 18681167. The next prime is 18681203. The reversal of 18681197 is 79118681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17732521 + 948676 = 4211^2 + 974^2 .

It is an emirp because it is prime and its reverse (79118681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18681197 - 2¹⁶ = 18615661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18681167) 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, 9340598 + 9340599.

It is an arithmetic number, because the mean of its divisors is an integer number (9340599).

Almost surely, 2^18681197 is an apocalyptic number.

It is an amenable number.

18681197 is a deficient number, since it is larger than the sum of its proper divisors (1).

18681197 is an equidigital number, since it uses as much as digits as its factorization.

18681197 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 18681197 is about 4322.1750311620. The cubic root of 18681197 is about 265.3392924696.

The spelling of 18681197 in words is "eighteen million, six hundred eighty-one thousand, one hundred ninety-seven".