666819216 has 140 divisors (see below), whose sum is σ = 2214050752. Its totient is φ = 190496448.

The previous prime is 666819191. The next prime is 666819233. The reversal of 666819216 is 612918666.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

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 27 ways as a sum of consecutive naturals, for example, 77565 + ... + 85731.

Almost surely, 2^666819216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666819216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1107025376).

666819216 is an abundant number, since it is smaller than the sum of its proper divisors (1547231536).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

666819216 is an equidigital number, since it uses as much as digits as its factorization.

666819216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8200 (or 8179 counting only the distinct ones).

The product of its digits is 186624, while the sum is 45.

The square root of 666819216 is about 25822.8429108803. The cubic root of 666819216 is about 873.6470917134.

The spelling of 666819216 in words is "six hundred sixty-six million, eight hundred nineteen thousand, two hundred sixteen".