66809117 has 4 divisors (see below), whose sum is σ = 67806336. Its totient is φ = 65811900.

The previous prime is 66809077. The next prime is 66809153. The reversal of 66809117 is 71190866.

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 not a de Polignac number, because 66809117 - 2⁶ = 66809053 is a prime.

It is a super-2 number, since 2×66809117² = 8926916228639378, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66829117) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 498509 + ... + 498642.

It is an arithmetic number, because the mean of its divisors is an integer number (16951584).

Almost surely, 2^66809117 is an apocalyptic number.

66809117 is a gapful number since it is divisible by the number (67) formed by its first and last digit.

It is an amenable number.

66809117 is a deficient number, since it is larger than the sum of its proper divisors (997219).

66809117 is an equidigital number, since it uses as much as digits as its factorization.

66809117 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 997218.

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 66809117 is about 8173.6844201376. The cubic root of 66809117 is about 405.7687314816.

The spelling of 66809117 in words is "sixty-six million, eight hundred nine thousand, one hundred seventeen".