91023 has 4 divisors (see below), whose sum is σ = 121368. Its totient is φ = 60680.

The previous prime is 91019. The next prime is 91033. The reversal of 91023 is 32019.

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 91023 - 2² = 91019 is a prime.

It is a D-number.

91023 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 90993 and 91011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91033) 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, 15168 + ... + 15173.

It is an arithmetic number, because the mean of its divisors is an integer number (30342).

2⁹¹⁰²³ is an apocalyptic number.

91023 is a deficient number, since it is larger than the sum of its proper divisors (30345).

91023 is a wasteful number, since it uses less digits than its factorization.

91023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30344.

The product of its (nonzero) digits is 54, while the sum is 15.

The square root of 91023 is about 301.7001823002. The cubic root of 91023 is about 44.9832036080.

The spelling of 91023 in words is "ninety-one thousand, twenty-three".