66188557321 has 2 divisors, whose sum is σ = 66188557322. Its totient is φ = 66188557320.

The previous prime is 66188557313. The next prime is 66188557381. The reversal of 66188557321 is 12375588166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 63784028025 + 2404529296 = 252555^2 + 49036^2 .

It is a cyclic number.

It is not a de Polignac number, because 66188557321 - 2³ = 66188557313 is a prime.

It is not a weakly prime, because it can be changed into another prime (66188557381) 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, 33094278660 + 33094278661.

It is an arithmetic number, because the mean of its divisors is an integer number (33094278661).

Almost surely, 2^66188557321 is an apocalyptic number.

It is an amenable number.

66188557321 is a deficient number, since it is larger than the sum of its proper divisors (1).

66188557321 is an equidigital number, since it uses as much as digits as its factorization.

66188557321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2419200, while the sum is 52.

The spelling of 66188557321 in words is "sixty-six billion, one hundred eighty-eight million, five hundred fifty-seven thousand, three hundred twenty-one".