90091 has 4 divisors (see below), whose sum is σ = 94032. Its totient is φ = 86152.

The previous prime is 90089. The next prime is 90107. The reversal of 90091 is 19009.

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 90091 - 2¹ = 90089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (90001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1936 + ... + 1981.

It is an arithmetic number, because the mean of its divisors is an integer number (23508).

2⁹⁰⁰⁹¹ is an apocalyptic number.

90091 is a deficient number, since it is larger than the sum of its proper divisors (3941).

90091 is a wasteful number, since it uses less digits than its factorization.

90091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3940.

The product of its (nonzero) digits is 81, while the sum is 19.

The square root of 90091 is about 300.1516283481. The cubic root of 90091 is about 44.8291463716.

The spelling of 90091 in words is "ninety thousand, ninety-one".