8043238721 has 12 divisors (see below), whose sum is σ = 9368205588. Its totient is φ = 6885520992.

The previous prime is 8043238717. The next prime is 8043238799. The reversal of 8043238721 is 1278323408.

It can be written as a sum of positive squares in 2 ways, for example, as 5873076496 + 2170162225 = 76636^2 + 46585^2 .

It is not a de Polignac number, because 8043238721 - 2² = 8043238717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (8043232721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 63926 + ... + 142031.

It is an arithmetic number, because the mean of its divisors is an integer number (780683799).

Almost surely, 2^8043238721 is an apocalyptic number.

It is an amenable number.

8043238721 is a deficient number, since it is larger than the sum of its proper divisors (1324966867).

8043238721 is a wasteful number, since it uses less digits than its factorization.

8043238721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206768 (or 206761 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 38.

The square root of 8043238721 is about 89684.1051747744. The cubic root of 8043238721 is about 2003.5967545509.

The spelling of 8043238721 in words is "eight billion, forty-three million, two hundred thirty-eight thousand, seven hundred twenty-one".