66779321209 has 2 divisors, whose sum is σ = 66779321210. Its totient is φ = 66779321208.

The previous prime is 66779321113. The next prime is 66779321221. The reversal of 66779321209 is 90212397766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 53718259984 + 13061061225 = 231772^2 + 114285^2 .

It is a cyclic number.

It is not a de Polignac number, because 66779321209 - 2²⁹ = 66242450297 is a prime.

It is a super-2 number, since 2×66779321209² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66779321249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33389660604 + 33389660605.

It is an arithmetic number, because the mean of its divisors is an integer number (33389660605).

Almost surely, 2^66779321209 is an apocalyptic number.

It is an amenable number.

66779321209 is a deficient number, since it is larger than the sum of its proper divisors (1).

66779321209 is an equidigital number, since it uses as much as digits as its factorization.

66779321209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1714608, while the sum is 52.

The spelling of 66779321209 in words is "sixty-six billion, seven hundred seventy-nine million, three hundred twenty-one thousand, two hundred nine".