18209197 has 2 divisors, whose sum is σ = 18209198. Its totient is φ = 18209196.

The previous prime is 18209173. The next prime is 18209203. The reversal of 18209197 is 79190281.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12187081 + 6022116 = 3491^2 + 2454^2 .

It is a cyclic number.

It is not a de Polignac number, because 18209197 - 2¹⁵ = 18176429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18209137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9104598 + 9104599.

It is an arithmetic number, because the mean of its divisors is an integer number (9104599).

Almost surely, 2^18209197 is an apocalyptic number.

It is an amenable number.

18209197 is a deficient number, since it is larger than the sum of its proper divisors (1).

18209197 is an equidigital number, since it uses as much as digits as its factorization.

18209197 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 18209197 is about 4267.2235704261. The cubic root of 18209197 is about 263.0855114769.

The spelling of 18209197 in words is "eighteen million, two hundred nine thousand, one hundred ninety-seven".