191730689257 has 2 divisors, whose sum is σ = 191730689258. Its totient is φ = 191730689256.

The previous prime is 191730689167. The next prime is 191730689287. The reversal of 191730689257 is 752986037191.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 188476671321 + 3254017936 = 434139^2 + 57044^2 .

It is a cyclic number.

It is not a de Polignac number, because 191730689257 - 2¹¹ = 191730687209 is a prime.

It is not a weakly prime, because it can be changed into another prime (191730689287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95865344628 + 95865344629.

It is an arithmetic number, because the mean of its divisors is an integer number (95865344629).

Almost surely, 2^191730689257 is an apocalyptic number.

It is an amenable number.

191730689257 is a deficient number, since it is larger than the sum of its proper divisors (1).

191730689257 is an equidigital number, since it uses as much as digits as its factorization.

191730689257 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5715360, while the sum is 58.

The spelling of 191730689257 in words is "one hundred ninety-one billion, seven hundred thirty million, six hundred eighty-nine thousand, two hundred fifty-seven".