66878709193 has 2 divisors, whose sum is σ = 66878709194. Its totient is φ = 66878709192.

The previous prime is 66878709169. The next prime is 66878709259. The reversal of 66878709193 is 39190787866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58969808569 + 7908900624 = 242837^2 + 88932^2 .

It is a cyclic number.

It is not a de Polignac number, because 66878709193 - 2⁹ = 66878708681 is a prime.

It is a super-2 number, since 2×66878709193² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66878709593) 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, 33439354596 + 33439354597.

It is an arithmetic number, because the mean of its divisors is an integer number (33439354597).

Almost surely, 2^66878709193 is an apocalyptic number.

It is an amenable number.

66878709193 is a deficient number, since it is larger than the sum of its proper divisors (1).

66878709193 is an equidigital number, since it uses as much as digits as its factorization.

66878709193 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27433728, while the sum is 64.

The spelling of 66878709193 in words is "sixty-six billion, eight hundred seventy-eight million, seven hundred nine thousand, one hundred ninety-three".