2291 has 4 divisors (see below), whose sum is σ = 2400.
Its totient is φ = 2184.
The previous prime is 2287. The next prime is 2293. The reversal of 2291 is 1922.
It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.
It is a cyclic number.
It is not a de Polignac number, because 2291 - 22 = 2287 is a prime.
It is a Duffinian number.
It is a plaindrome in base 12.
It is a nialpdrome in base 14.
It is not an unprimeable number, because it can be changed into a prime (2293) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (7) of ones.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11 + ... + 68.
It is an arithmetic number, because the mean of its divisors is an integer number (600).
22291 is an apocalyptic number.
2291 is a deficient number, since it is larger than the sum of its proper divisors (109).
2291 is an equidigital number, since it uses as much as digits as its factorization.
2291 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 108.
The product of its digits is 36, while the sum is 14.
The square root of 2291 is about 47.8643917751.
The cubic root of 2291 is about 13.1828212403.
It can be divided in two parts, 22 and 91, that multiplied together give a palindrome (2002).
The spelling of 2291 in words is "two thousand, two hundred ninety-one".