2005266581 has 12 divisors (see below), whose sum is σ = 2059681092. Its totient is φ = 1952256000.

The previous prime is 2005266577. The next prime is 2005266611. The reversal of 2005266581 is 1856625002.

It can be written as a sum of positive squares in 6 ways, for example, as 844774225 + 1160492356 = 29065^2 + 34066^2 .

It is not a de Polignac number, because 2005266581 - 2² = 2005266577 is a prime.

It is a super-2 number, since 2×2005266581² = 8042188121750859122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2005266511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1076591 + ... + 1078451.

It is an arithmetic number, because the mean of its divisors is an integer number (171640091).

Almost surely, 2^2005266581 is an apocalyptic number.

It is an amenable number.

2005266581 is a deficient number, since it is larger than the sum of its proper divisors (54414511).

2005266581 is an equidigital number, since it uses as much as digits as its factorization.

2005266581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2584 (or 2543 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 35.

The square root of 2005266581 is about 44780.2030031129. The cubic root of 2005266581 is about 1261.0259932932.

The spelling of 2005266581 in words is "two billion, five million, two hundred sixty-six thousand, five hundred eighty-one".