2101891 has 12 divisors (see below), whose sum is σ = 2394000. Its totient is φ = 1841840.

The previous prime is 2101873. The next prime is 2101903. The reversal of 2101891 is 1981012.

It is not a de Polignac number, because 2101891 - 2¹³ = 2093699 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2101811) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3210 + ... + 3808.

It is an arithmetic number, because the mean of its divisors is an integer number (199500).

2^2101891 is an apocalyptic number.

2101891 is a deficient number, since it is larger than the sum of its proper divisors (292109).

2101891 is a wasteful number, since it uses less digits than its factorization.

2101891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 650 (or 639 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 22.

The square root of 2101891 is about 1449.7899847909. The cubic root of 2101891 is about 128.0963426687.

It can be divided in two parts, 2101 and 891, that added together give a palindrome (2992).

The spelling of 2101891 in words is "two million, one hundred one thousand, eight hundred ninety-one".