66916809 has 12 divisors (see below), whose sum is σ = 96797376. Its totient is φ = 44546712.

The previous prime is 66916789. The next prime is 66916813. The reversal of 66916809 is 90861966.

It is not a de Polignac number, because 66916809 - 2¹¹ = 66914761 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66916819) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1684 + ... + 11690.

It is an arithmetic number, because the mean of its divisors is an integer number (8066448).

Almost surely, 2^66916809 is an apocalyptic number.

It is an amenable number.

66916809 is a deficient number, since it is larger than the sum of its proper divisors (29880567).

66916809 is a wasteful number, since it uses less digits than its factorization.

66916809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10756 (or 10753 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The square root of 66916809 is about 8180.2694943382. The cubic root of 66916809 is about 405.9866388058.

The spelling of 66916809 in words is "sixty-six million, nine hundred sixteen thousand, eight hundred nine".