43939921 has 4 divisors (see below), whose sum is σ = 43955892. Its totient is φ = 43923952.

The previous prime is 43939897. The next prime is 43939957. The reversal of 43939921 is 12993934.

43939921 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 16524225 + 27415696 = 4065^2 + 5236^2 .

It is a cyclic number.

It is not a de Polignac number, because 43939921 - 2⁷ = 43939793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (43939981) 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, 2686 + ... + 9751.

It is an arithmetic number, because the mean of its divisors is an integer number (10988973).

Almost surely, 2^43939921 is an apocalyptic number.

It is an amenable number.

43939921 is a deficient number, since it is larger than the sum of its proper divisors (15971).

43939921 is a wasteful number, since it uses less digits than its factorization.

43939921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15970.

The product of its digits is 52488, while the sum is 40.

The square root of 43939921 is about 6628.7194087546. The cubic root of 43939921 is about 352.8740786789.

The spelling of 43939921 in words is "forty-three million, nine hundred thirty-nine thousand, nine hundred twenty-one".