2271991 has 4 divisors (see below), whose sum is σ = 2324872. Its totient is φ = 2219112.

The previous prime is 2271989. The next prime is 2272013. The reversal of 2271991 is 1991722.

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 2271991 - 2¹ = 2271989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2271901) 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, 26376 + ... + 26461.

It is an arithmetic number, because the mean of its divisors is an integer number (581218).

2^2271991 is an apocalyptic number.

2271991 is a deficient number, since it is larger than the sum of its proper divisors (52881).

2271991 is an equidigital number, since it uses as much as digits as its factorization.

2271991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52880.

The product of its digits is 2268, while the sum is 31.

The square root of 2271991 is about 1507.3125090704. The cubic root of 2271991 is about 131.4625954422.

The spelling of 2271991 in words is "two million, two hundred seventy-one thousand, nine hundred ninety-one".