191657 has 2 divisors, whose sum is σ = 191658. Its totient is φ = 191656.

The previous prime is 191627. The next prime is 191669. The reversal of 191657 is 756191.

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., 179776 + 11881 = 424^2 + 109^2 .

It is an emirp because it is prime and its reverse (756191) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 191657 - 2¹⁰ = 190633 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 191657.

It is not a weakly prime, because it can be changed into another prime (191627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95828 + 95829.

It is an arithmetic number, because the mean of its divisors is an integer number (95829).

2¹⁹¹⁶⁵⁷ is an apocalyptic number.

It is an amenable number.

191657 is a deficient number, since it is larger than the sum of its proper divisors (1).

191657 is an equidigital number, since it uses as much as digits as its factorization.

191657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1890, while the sum is 29.

The square root of 191657 is about 437.7864776349. The cubic root of 191657 is about 57.6556087514.

It can be divided in two parts, 191 and 657, that added together give a palindrome (848).

The spelling of 191657 in words is "one hundred ninety-one thousand, six hundred fifty-seven".