66418109 has 2 divisors, whose sum is σ = 66418110. Its totient is φ = 66418108.

The previous prime is 66418103. The next prime is 66418111. The reversal of 66418109 is 90181466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 58094884 + 8323225 = 7622^2 + 2885^2 .

It is a cyclic number.

It is not a de Polignac number, because 66418109 - 2⁸ = 66417853 is a prime.

It is a super-2 number, since 2×66418109² = 8822730406271762, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 66418111, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66418103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33209054 + 33209055.

It is an arithmetic number, because the mean of its divisors is an integer number (33209055).

Almost surely, 2^66418109 is an apocalyptic number.

It is an amenable number.

66418109 is a deficient number, since it is larger than the sum of its proper divisors (1).

66418109 is an equidigital number, since it uses as much as digits as its factorization.

66418109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 66418109 is about 8149.7306090447. The cubic root of 66418109 is about 404.9755794857.

The spelling of 66418109 in words is "sixty-six million, four hundred eighteen thousand, one hundred nine".