66586561 has 2 divisors, whose sum is σ = 66586562. Its totient is φ = 66586560.

The previous prime is 66586549. The next prime is 66586567. The reversal of 66586561 is 16568566.

66586561 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., 66585600 + 961 = 8160^2 + 31^2 .

It is a cyclic number.

It is not a de Polignac number, because 66586561 - 2⁵ = 66586529 is a prime.

It is not a weakly prime, because it can be changed into another prime (66586567) 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 as a sum of consecutive naturals, namely, 33293280 + 33293281.

It is an arithmetic number, because the mean of its divisors is an integer number (33293281).

Almost surely, 2^66586561 is an apocalyptic number.

It is an amenable number.

66586561 is a deficient number, since it is larger than the sum of its proper divisors (1).

66586561 is an equidigital number, since it uses as much as digits as its factorization.

66586561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 259200, while the sum is 43.

The square root of 66586561 is about 8160.0588845915. The cubic root of 66586561 is about 405.3176616646.

The spelling of 66586561 in words is "sixty-six million, five hundred eighty-six thousand, five hundred sixty-one".