40091 has 4 divisors (see below), whose sum is σ = 40992. Its totient is φ = 39192.

The previous prime is 40087. The next prime is 40093. The reversal of 40091 is 19004.

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 40091 - 2² = 40087 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40093) 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, 380 + ... + 473.

It is an arithmetic number, because the mean of its divisors is an integer number (10248).

2⁴⁰⁰⁹¹ is an apocalyptic number.

40091 is a deficient number, since it is larger than the sum of its proper divisors (901).

40091 is an equidigital number, since it uses as much as digits as its factorization.

40091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 900.

The product of its (nonzero) digits is 36, while the sum is 14.

The square root of 40091 is about 200.2273707563. The cubic root of 40091 is about 34.2254339264.

Adding to 40091 its reverse (19004), we get a palindrome (59095).

The spelling of 40091 in words is "forty thousand, ninety-one".