66705109 has 2 divisors, whose sum is σ = 66705110. Its totient is φ = 66705108.

The previous prime is 66705097. The next prime is 66705113. The reversal of 66705109 is 90150766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 59830225 + 6874884 = 7735^2 + 2622^2 .

It is a cyclic number.

It is not a de Polignac number, because 66705109 - 2¹¹ = 66703061 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66705179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33352554 + 33352555.

It is an arithmetic number, because the mean of its divisors is an integer number (33352555).

Almost surely, 2^66705109 is an apocalyptic number.

It is an amenable number.

66705109 is a deficient number, since it is larger than the sum of its proper divisors (1).

66705109 is an equidigital number, since it uses as much as digits as its factorization.

66705109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11340, while the sum is 34.

The square root of 66705109 is about 8167.3195725403. The cubic root of 66705109 is about 405.5580560746.

The spelling of 66705109 in words is "sixty-six million, seven hundred five thousand, one hundred nine".