It is a happy number.
It is a strong prime.
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-166819949 is a prime.
It is a Sophie Germain prime.
It is a Chen prime.
It is a Curzon number.
It is a self number, because there is not a number n which added to its sum of digits gives 166819949.
It is a congruent number.
Almost surely, 2166819949 is an apocalyptic number.
It is an amenable number.
166819949 is an equidigital number, since it uses as much as digits as its factorization.
166819949 is an evil number, because the sum of its binary digits is even.
The square root of 166819949 is about 12915.8797222644. The cubic root of 166819949 is about 550.4898654930.
The spelling of 166819949 in words is "one hundred sixty-six million, eight hundred nineteen thousand, nine hundred forty-nine".