2081691 has 6 divisors (see below), whose sum is σ = 3006900. Its totient is φ = 1387788.

The previous prime is 2081687. The next prime is 2081719. The reversal of 2081691 is 1961802.

It is not a de Polignac number, because 2081691 - 2² = 2081687 is a prime.

2081691 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2081671) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 115641 + ... + 115658.

It is an arithmetic number, because the mean of its divisors is an integer number (501150).

2^2081691 is an apocalyptic number.

2081691 is a deficient number, since it is larger than the sum of its proper divisors (925209).

2081691 is a wasteful number, since it uses less digits than its factorization.

2081691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231305 (or 231302 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 2081691 is about 1442.8066398516. The cubic root of 2081691 is about 127.6846689622.

It can be divided in two parts, 2081 and 691, that added together give a palindrome (2772).

The spelling of 2081691 in words is "two million, eighty-one thousand, six hundred ninety-one".