66808468409 has 4 divisors (see below), whose sum is σ = 67497215604. Its totient is φ = 66119721216.

The previous prime is 66808468361. The next prime is 66808468417. The reversal of 66808468409 is 90486480866.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 20175361600 + 46633106809 = 142040^2 + 215947^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66808468409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66808468429) 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 in 3 ways as a sum of consecutive naturals, for example, 344373452 + ... + 344373645.

It is an arithmetic number, because the mean of its divisors is an integer number (16874303901).

Almost surely, 2^66808468409 is an apocalyptic number.

It is an amenable number.

66808468409 is a deficient number, since it is larger than the sum of its proper divisors (688747195).

66808468409 is an equidigital number, since it uses as much as digits as its factorization.

66808468409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 688747194.

The product of its (nonzero) digits is 15925248, while the sum is 59.

The spelling of 66808468409 in words is "sixty-six billion, eight hundred eight million, four hundred sixty-eight thousand, four hundred nine".