66809101 has 4 divisors (see below), whose sum is σ = 67063392. Its totient is φ = 66554812.

The previous prime is 66809077. The next prime is 66809153. The reversal of 66809101 is 10190866.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66809101 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66809191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 126751 + ... + 127276.

It is an arithmetic number, because the mean of its divisors is an integer number (16765848).

Almost surely, 2^66809101 is an apocalyptic number.

It is an amenable number.

66809101 is a deficient number, since it is larger than the sum of its proper divisors (254291).

66809101 is a wasteful number, since it uses less digits than its factorization.

66809101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 254290.

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 66809101 is about 8173.6834413868. The cubic root of 66809101 is about 405.7686990893.

Adding to 66809101 its reverse (10190866), we get a palindrome (76999967).

The spelling of 66809101 in words is "sixty-six million, eight hundred nine thousand, one hundred one".