2005581 has 4 divisors (see below), whose sum is σ = 2674112. Its totient is φ = 1337052.

The previous prime is 2005579. The next prime is 2005613. The reversal of 2005581 is 1855002.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 2005581 - 2¹ = 2005579 is a prime.

It is a super-2 number, since 2×2005581² = 8044710295122, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2005571) 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, 334261 + ... + 334266.

It is an arithmetic number, because the mean of its divisors is an integer number (668528).

2^2005581 is an apocalyptic number.

It is an amenable number.

2005581 is a deficient number, since it is larger than the sum of its proper divisors (668531).

2005581 is an equidigital number, since it uses as much as digits as its factorization.

2005581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 668530.

The product of its (nonzero) digits is 400, while the sum is 21.

The square root of 2005581 is about 1416.1853692225. The cubic root of 2005581 is about 126.1091898049.

The spelling of 2005581 in words is "two million, five thousand, five hundred eighty-one".