185640197 has 2 divisors, whose sum is σ = 185640198. Its totient is φ = 185640196.

The previous prime is 185640193. The next prime is 185640239. The reversal of 185640197 is 791046581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 185123236 + 516961 = 13606^2 + 719^2 .

It is a cyclic number.

It is not a de Polignac number, because 185640197 - 2² = 185640193 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (185640193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 92820098 + 92820099.

It is an arithmetic number, because the mean of its divisors is an integer number (92820099).

Almost surely, 2^185640197 is an apocalyptic number.

It is an amenable number.

185640197 is a deficient number, since it is larger than the sum of its proper divisors (1).

185640197 is an equidigital number, since it uses as much as digits as its factorization.

185640197 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60480, while the sum is 41.

The square root of 185640197 is about 13624.9842935689. The cubic root of 185640197 is about 570.4584359537.

The spelling of 185640197 in words is "one hundred eighty-five million, six hundred forty thousand, one hundred ninety-seven".