2005691 has 4 divisors (see below), whose sum is σ = 2016384. Its totient is φ = 1995000.

The previous prime is 2005687. The next prime is 2005693. The reversal of 2005691 is 1965002.

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 2005691 - 2² = 2005687 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2005693) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5060 + ... + 5441.

It is an arithmetic number, because the mean of its divisors is an integer number (504096).

2^2005691 is an apocalyptic number.

2005691 is a deficient number, since it is larger than the sum of its proper divisors (10693).

2005691 is a wasteful number, since it uses less digits than its factorization.

2005691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10692.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 2005691 is about 1416.2242054138. The cubic root of 2005691 is about 126.1114953308. Note that the first 3 decimals are identical.

The spelling of 2005691 in words is "two million, five thousand, six hundred ninety-one".