66661109 has 2 divisors, whose sum is σ = 66661110. Its totient is φ = 66661108.

The previous prime is 66661103. The next prime is 66661151. The reversal of 66661109 is 90116666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 56580484 + 10080625 = 7522^2 + 3175^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66661109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66661103) 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, 33330554 + 33330555.

It is an arithmetic number, because the mean of its divisors is an integer number (33330555).

Almost surely, 2^66661109 is an apocalyptic number.

It is an amenable number.

66661109 is a deficient number, since it is larger than the sum of its proper divisors (1).

66661109 is an equidigital number, since it uses as much as digits as its factorization.

66661109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 66661109 is about 8164.6254659966. The cubic root of 66661109 is about 405.4688651080.

The spelling of 66661109 in words is "sixty-six million, six hundred sixty-one thousand, one hundred nine".