191688313 has 2 divisors, whose sum is σ = 191688314. Its totient is φ = 191688312.

The previous prime is 191688293. The next prime is 191688317. The reversal of 191688313 is 313886191.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 180311184 + 11377129 = 13428^2 + 3373^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-191688313 is a prime.

It is not a weakly prime, because it can be changed into another prime (191688317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95844156 + 95844157.

It is an arithmetic number, because the mean of its divisors is an integer number (95844157).

Almost surely, 2^191688313 is an apocalyptic number.

It is an amenable number.

191688313 is a deficient number, since it is larger than the sum of its proper divisors (1).

191688313 is an equidigital number, since it uses as much as digits as its factorization.

191688313 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31104, while the sum is 40.

The square root of 191688313 is about 13845.1548564832. The cubic root of 191688313 is about 576.5874851279.

The spelling of 191688313 in words is "one hundred ninety-one million, six hundred eighty-eight thousand, three hundred thirteen".