43640581 has 16 divisors (see below), whose sum is σ = 47602944. Its totient is φ = 39849984.

The previous prime is 43640573. The next prime is 43640609. The reversal of 43640581 is 18504634.

It is a happy number.

43640581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 43640581 - 2³ = 43640573 is a prime.

It is a super-2 number, since 2×43640581² = 3809000620035122, 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 (43640081) 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 15 ways as a sum of consecutive naturals, for example, 154066 + ... + 154348.

It is an arithmetic number, because the mean of its divisors is an integer number (2975184).

Almost surely, 2^43640581 is an apocalyptic number.

It is an amenable number.

43640581 is a deficient number, since it is larger than the sum of its proper divisors (3962363).

43640581 is a wasteful number, since it uses less digits than its factorization.

43640581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 540.

The product of its (nonzero) digits is 11520, while the sum is 31.

The square root of 43640581 is about 6606.1018006083. The cubic root of 43640581 is about 352.0709357943.

The spelling of 43640581 in words is "forty-three million, six hundred forty thousand, five hundred eighty-one".