91391 has 4 divisors (see below), whose sum is σ = 93000. Its totient is φ = 89784.

The previous prime is 91387. The next prime is 91393. The reversal of 91391 is 19319.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 91391 - 2² = 91387 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 91391.

It is not an unprimeable number, because it can be changed into a prime (91393) 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, 716 + ... + 833.

It is an arithmetic number, because the mean of its divisors is an integer number (23250).

2⁹¹³⁹¹ is an apocalyptic number.

91391 is a deficient number, since it is larger than the sum of its proper divisors (1609).

91391 is a wasteful number, since it uses less digits than its factorization.

91391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1608.

The product of its digits is 243, while the sum is 23.

The square root of 91391 is about 302.3094441131. The cubic root of 91391 is about 45.0437434724.

The spelling of 91391 in words is "ninety-one thousand, three hundred ninety-one".