2231991 has 6 divisors (see below), whose sum is σ = 3224000. Its totient is φ = 1487988.

The previous prime is 2231941. The next prime is 2232017. The reversal of 2231991 is 1991322.

2231991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 2231991 - 2⁹ = 2231479 is a prime.

It is a super-3 number, since 3×2231991³ = 33357889977883125813, which contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2231941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 123991 + ... + 124008.

2^2231991 is an apocalyptic number.

2231991 is a deficient number, since it is larger than the sum of its proper divisors (992009).

2231991 is a wasteful number, since it uses less digits than its factorization.

2231991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248005 (or 248002 counting only the distinct ones).

The product of its digits is 972, while the sum is 27.

The square root of 2231991 is about 1493.9849396831. The cubic root of 2231991 is about 130.6865258873.

The spelling of 2231991 in words is "two million, two hundred thirty-one thousand, nine hundred ninety-one".