191662520857 has 2 divisors, whose sum is σ = 191662520858. Its totient is φ = 191662520856.

The previous prime is 191662520837. The next prime is 191662520867. The reversal of 191662520857 is 758025266191.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 105247687561 + 86414833296 = 324419^2 + 293964^2 .

It is a cyclic number.

It is not a de Polignac number, because 191662520857 - 2¹⁵ = 191662488089 is a prime.

It is not a weakly prime, because it can be changed into another prime (191662520837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95831260428 + 95831260429.

It is an arithmetic number, because the mean of its divisors is an integer number (95831260429).

Almost surely, 2^191662520857 is an apocalyptic number.

It is an amenable number.

191662520857 is a deficient number, since it is larger than the sum of its proper divisors (1).

191662520857 is an equidigital number, since it uses as much as digits as its factorization.

191662520857 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1814400, while the sum is 52.

The spelling of 191662520857 in words is "one hundred ninety-one billion, six hundred sixty-two million, five hundred twenty thousand, eight hundred fifty-seven".