66724393 has 2 divisors, whose sum is σ = 66724394. Its totient is φ = 66724392.

The previous prime is 66724391. The next prime is 66724397. The reversal of 66724393 is 39342766.

66724393 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51451929 + 15272464 = 7173^2 + 3908^2 .

It is a cyclic number.

It is not a de Polignac number, because 66724393 - 2¹ = 66724391 is a prime.

Together with 66724391, it forms a pair of twin primes.

It is the 8169-th Hogben number.

It is a zygodrome in base 3.

It is not a weakly prime, because it can be changed into another prime (66724391) by changing a digit.

It is a nontrivial repunit in base 8168.

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 as a sum of consecutive naturals, namely, 33362196 + 33362197.

It is an arithmetic number, because the mean of its divisors is an integer number (33362197).

Almost surely, 2^66724393 is an apocalyptic number.

It is an amenable number.

66724393 is a deficient number, since it is larger than the sum of its proper divisors (1).

66724393 is an equidigital number, since it uses as much as digits as its factorization.

66724393 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 163296, while the sum is 40.

The square root of 66724393 is about 8168.5000459081. The cubic root of 66724393 is about 405.5971336812.

The spelling of 66724393 in words is "sixty-six million, seven hundred twenty-four thousand, three hundred ninety-three".