2001891 has 8 divisors (see below), whose sum is σ = 2677840. Its totient is φ = 1330272.

The previous prime is 2001847. The next prime is 2001911. The reversal of 2001891 is 1981002.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2001891 - 2¹³ = 1993699 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2001191) 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 7 ways as a sum of consecutive naturals, for example, 225 + ... + 2013.

It is an arithmetic number, because the mean of its divisors is an integer number (334730).

2^2001891 is an apocalyptic number.

2001891 is a deficient number, since it is larger than the sum of its proper divisors (675949).

2001891 is a wasteful number, since it uses less digits than its factorization.

2001891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2165.

The product of its (nonzero) digits is 144, while the sum is 21.

The square root of 2001891 is about 1414.8819738763. The cubic root of 2001891 is about 126.0318009930.

Adding to 2001891 its reverse (1981002), we get a palindrome (3982893).

The spelling of 2001891 in words is "two million, one thousand, eight hundred ninety-one".