66723109 has 2 divisors, whose sum is σ = 66723110. Its totient is φ = 66723108.

The previous prime is 66723077. The next prime is 66723121. The reversal of 66723109 is 90132766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 45360225 + 21362884 = 6735^2 + 4622^2 .

It is a cyclic number.

It is not a de Polignac number, because 66723109 - 2⁵ = 66723077 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66723179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33361554 + 33361555.

It is an arithmetic number, because the mean of its divisors is an integer number (33361555).

Almost surely, 2^66723109 is an apocalyptic number.

It is an amenable number.

66723109 is a deficient number, since it is larger than the sum of its proper divisors (1).

66723109 is an equidigital number, since it uses as much as digits as its factorization.

66723109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13608, while the sum is 34.

The square root of 66723109 is about 8168.4214509292. The cubic root of 66723109 is about 405.5945319837.

The spelling of 66723109 in words is "sixty-six million, seven hundred twenty-three thousand, one hundred nine".