43681581 has 6 divisors (see below), whose sum is σ = 63095630. Its totient is φ = 29121048.

The previous prime is 43681567. The next prime is 43681597. The reversal of 43681581 is 18518634.

43681581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 32592681 + 11088900 = 5709^2 + 3330^2 .

It is not a de Polignac number, because 43681581 - 2⁹ = 43681069 is a prime.

It is a super-2 number, since 2×43681581² = 3816161037319122, 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 (43681501) 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 5 ways as a sum of consecutive naturals, for example, 2426746 + ... + 2426763.

Almost surely, 2^43681581 is an apocalyptic number.

It is an amenable number.

43681581 is a deficient number, since it is larger than the sum of its proper divisors (19414049).

43681581 is a wasteful number, since it uses less digits than its factorization.

43681581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4853515 (or 4853512 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The square root of 43681581 is about 6609.2042637522. The cubic root of 43681581 is about 352.1811572892.

The spelling of 43681581 in words is "forty-three million, six hundred eighty-one thousand, five hundred eighty-one".