66505131613 has 2 divisors, whose sum is σ = 66505131614. Its totient is φ = 66505131612.

The previous prime is 66505131587. The next prime is 66505131631. The reversal of 66505131613 is 31613150566.

Together with next prime (66505131631) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 40170982329 + 26334149284 = 200427^2 + 162278^2 .

It is a cyclic number.

It is not a de Polignac number, because 66505131613 - 2⁹ = 66505131101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66505131013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33252565806 + 33252565807.

It is an arithmetic number, because the mean of its divisors is an integer number (33252565807).

Almost surely, 2^66505131613 is an apocalyptic number.

It is an amenable number.

66505131613 is a deficient number, since it is larger than the sum of its proper divisors (1).

66505131613 is an equidigital number, since it uses as much as digits as its factorization.

66505131613 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48600, while the sum is 37.

The spelling of 66505131613 in words is "sixty-six billion, five hundred five million, one hundred thirty-one thousand, six hundred thirteen".