66656530321 has 2 divisors, whose sum is σ = 66656530322. Its totient is φ = 66656530320.

The previous prime is 66656530319. The next prime is 66656530333. The reversal of 66656530321 is 12303565666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64890429696 + 1766100625 = 254736^2 + 42025^2 .

It is a cyclic number.

It is not a de Polignac number, because 66656530321 - 2¹ = 66656530319 is a prime.

Together with 66656530319, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (66656530921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33328265160 + 33328265161.

It is an arithmetic number, because the mean of its divisors is an integer number (33328265161).

Almost surely, 2^66656530321 is an apocalyptic number.

It is an amenable number.

66656530321 is a deficient number, since it is larger than the sum of its proper divisors (1).

66656530321 is an equidigital number, since it uses as much as digits as its factorization.

66656530321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 583200, while the sum is 43.

The spelling of 66656530321 in words is "sixty-six billion, six hundred fifty-six million, five hundred thirty thousand, three hundred twenty-one".