243040721 has 24 divisors (see below), whose sum is σ = 323285760. Its totient is φ = 178231680.

The previous prime is 243040717. The next prime is 243040727. The reversal of 243040721 is 127040342.

243040721 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 243040721 - 2² = 243040717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (243040727) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5960 + ... + 22838.

It is an arithmetic number, because the mean of its divisors is an integer number (13470240).

Almost surely, 2^243040721 is an apocalyptic number.

It is an amenable number.

243040721 is a deficient number, since it is larger than the sum of its proper divisors (80245039).

243040721 is a wasteful number, since it uses less digits than its factorization.

243040721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16925 (or 16914 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 23.

The square root of 243040721 is about 15589.7633400895. The cubic root of 243040721 is about 624.0600022087.

The spelling of 243040721 in words is "two hundred forty-three million, forty thousand, seven hundred twenty-one".