4066721 has 2 divisors, whose sum is σ = 4066722. Its totient is φ = 4066720.

The previous prime is 4066709. The next prime is 4066729. The reversal of 4066721 is 1276604.

4066721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2217121 + 1849600 = 1489^2 + 1360^2 .

It is a cyclic number.

It is not a de Polignac number, because 4066721 - 2¹⁰ = 4065697 is a prime.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (4066729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2033360 + 2033361.

It is an arithmetic number, because the mean of its divisors is an integer number (2033361).

Almost surely, 2^4066721 is an apocalyptic number.

It is an amenable number.

4066721 is a deficient number, since it is larger than the sum of its proper divisors (1).

4066721 is an equidigital number, since it uses as much as digits as its factorization.

4066721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 4066721 is about 2016.6112664567. The cubic root of 4066721 is about 159.6178510109.

The spelling of 4066721 in words is "four million, sixty-six thousand, seven hundred twenty-one".