186991697 has 2 divisors, whose sum is σ = 186991698. Its totient is φ = 186991696.

The previous prime is 186991669. The next prime is 186991699. The reversal of 186991697 is 796199681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 176597521 + 10394176 = 13289^2 + 3224^2 .

It is an emirp because it is prime and its reverse (796199681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 186991697 - 2²⁴ = 170214481 is a prime.

Together with 186991699, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (186991699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 93495848 + 93495849.

It is an arithmetic number, because the mean of its divisors is an integer number (93495849).

Almost surely, 2^186991697 is an apocalyptic number.

It is an amenable number.

186991697 is a deficient number, since it is larger than the sum of its proper divisors (1).

186991697 is an equidigital number, since it uses as much as digits as its factorization.

186991697 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1469664, while the sum is 56.

The square root of 186991697 is about 13674.4907400605. The cubic root of 186991697 is about 571.8394428090.

The spelling of 186991697 in words is "one hundred eighty-six million, nine hundred ninety-one thousand, six hundred ninety-seven".