43643021 has 4 divisors (see below), whose sum is σ = 43717212. Its totient is φ = 43568832.

The previous prime is 43643003. The next prime is 43643023. The reversal of 43643021 is 12034634.

It is a happy number.

43643021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 29278921 + 14364100 = 5411^2 + 3790^2 .

It is a cyclic number.

It is not a de Polignac number, because 43643021 - 2⁶ = 43642957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43643023) 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, 36206 + ... + 37391.

It is an arithmetic number, because the mean of its divisors is an integer number (10929303).

Almost surely, 2^43643021 is an apocalyptic number.

It is an amenable number.

43643021 is a deficient number, since it is larger than the sum of its proper divisors (74191).

43643021 is an equidigital number, since it uses as much as digits as its factorization.

43643021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74190.

The product of its (nonzero) digits is 1728, while the sum is 23.

The square root of 43643021 is about 6606.2864757744. The cubic root of 43643021 is about 352.0774972489.

Adding to 43643021 its reverse (12034634), we get a palindrome (55677655).

The spelling of 43643021 in words is "forty-three million, six hundred forty-three thousand, twenty-one".