191897 has 4 divisors (see below), whose sum is σ = 193536. Its totient is φ = 190260.

The previous prime is 191861. The next prime is 191899. The reversal of 191897 is 798191.

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 191897 - 2⁶ = 191833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (191899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 629 + ... + 882.

It is an arithmetic number, because the mean of its divisors is an integer number (48384).

2¹⁹¹⁸⁹⁷ is an apocalyptic number.

It is an amenable number.

191897 is a deficient number, since it is larger than the sum of its proper divisors (1639).

191897 is a wasteful number, since it uses less digits than its factorization.

191897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1638.

The product of its digits is 4536, while the sum is 35.

The square root of 191897 is about 438.0604981050. The cubic root of 191897 is about 57.6796648764.

The spelling of 191897 in words is "one hundred ninety-one thousand, eight hundred ninety-seven".