66556573 has 2 divisors, whose sum is σ = 66556574. Its totient is φ = 66556572.

The previous prime is 66556531. The next prime is 66556579. The reversal of 66556573 is 37565566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 38962564 + 27594009 = 6242^2 + 5253^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66556573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66556579) 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 as a sum of consecutive naturals, namely, 33278286 + 33278287.

It is an arithmetic number, because the mean of its divisors is an integer number (33278287).

Almost surely, 2^66556573 is an apocalyptic number.

It is an amenable number.

66556573 is a deficient number, since it is larger than the sum of its proper divisors (1).

66556573 is an equidigital number, since it uses as much as digits as its factorization.

66556573 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 567000, while the sum is 43.

The square root of 66556573 is about 8158.2211909215. The cubic root of 66556573 is about 405.2568060856.

The spelling of 66556573 in words is "sixty-six million, five hundred fifty-six thousand, five hundred seventy-three".