91897 has 4 divisors (see below), whose sum is σ = 98980. Its totient is φ = 84816.

The previous prime is 91873. The next prime is 91909. The reversal of 91897 is 79819.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79819 = 19 ⋅4201.

It can be written as a sum of positive squares in 2 ways, for example, as 22201 + 69696 = 149^2 + 264^2 .

It is a cyclic number.

It is not a de Polignac number, because 91897 - 2¹¹ = 89849 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 (91807) 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, 3522 + ... + 3547.

It is an arithmetic number, because the mean of its divisors is an integer number (24745).

2⁹¹⁸⁹⁷ is an apocalyptic number.

It is an amenable number.

91897 is a deficient number, since it is larger than the sum of its proper divisors (7083).

91897 is a wasteful number, since it uses less digits than its factorization.

91897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7082.

The product of its digits is 4536, while the sum is 34.

The square root of 91897 is about 303.1451797407. The cubic root of 91897 is about 45.1267210052.

The spelling of 91897 in words is "ninety-one thousand, eight hundred ninety-seven".