191257 has 4 divisors (see below), whose sum is σ = 208656. Its totient is φ = 173860.

The previous prime is 191251. The next prime is 191281. The reversal of 191257 is 752191.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 191257 - 2³ = 191249 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (191251) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8683 + ... + 8704.

It is an arithmetic number, because the mean of its divisors is an integer number (52164).

2¹⁹¹²⁵⁷ is an apocalyptic number.

It is an amenable number.

191257 is a deficient number, since it is larger than the sum of its proper divisors (17399).

191257 is a wasteful number, since it uses less digits than its factorization.

191257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17398.

The product of its digits is 630, while the sum is 25.

The square root of 191257 is about 437.3293953075. The cubic root of 191257 is about 57.6154705422.

The spelling of 191257 in words is "one hundred ninety-one thousand, two hundred fifty-seven".