5681581 has 4 divisors (see below), whose sum is σ = 5740252. Its totient is φ = 5622912.

The previous prime is 5681579. The next prime is 5681603. The reversal of 5681581 is 1851865.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1851865 = 5 ⋅370373.

It can be written as a sum of positive squares in 2 ways, for example, as 4691556 + 990025 = 2166^2 + 995^2 .

It is a cyclic number.

It is not a de Polignac number, because 5681581 - 2¹ = 5681579 is a prime.

It is a super-2 number, since 2×5681581² = 64560725319122, which contains 22 as substring.

It is a Duffinian number.

5681581 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5681521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29190 + ... + 29383.

It is an arithmetic number, because the mean of its divisors is an integer number (1435063).

Almost surely, 2^5681581 is an apocalyptic number.

It is an amenable number.

5681581 is a deficient number, since it is larger than the sum of its proper divisors (58671).

5681581 is an equidigital number, since it uses as much as digits as its factorization.

5681581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58670.

The product of its digits is 9600, while the sum is 34.

The square root of 5681581 is about 2383.6067209169. The cubic root of 5681581 is about 178.4389808879.

The spelling of 5681581 in words is "five million, six hundred eighty-one thousand, five hundred eighty-one".