66599557613 has 2 divisors, whose sum is σ = 66599557614. Its totient is φ = 66599557612.

The previous prime is 66599557579. The next prime is 66599557639. The reversal of 66599557613 is 31675599566.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63663868489 + 2935689124 = 252317^2 + 54182^2 .

It is a cyclic number.

It is not a de Polignac number, because 66599557613 - 2²⁰ = 66598509037 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66599550613) 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, 33299778806 + 33299778807.

It is an arithmetic number, because the mean of its divisors is an integer number (33299778807).

Almost surely, 2^66599557613 is an apocalyptic number.

It is an amenable number.

66599557613 is a deficient number, since it is larger than the sum of its proper divisors (1).

66599557613 is an equidigital number, since it uses as much as digits as its factorization.

66599557613 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 45927000, while the sum is 62.

The spelling of 66599557613 in words is "sixty-six billion, five hundred ninety-nine million, five hundred fifty-seven thousand, six hundred thirteen".