It is a happy number.
It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 958999999 = 349 ⋅2747851.
It is a cyclic number.
It is a Duffinian number.
Almost surely, 2999999859 is an apocalyptic number.
999999859 is a wasteful number, since it uses less digits than its factorization.
999999859 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 64156.
The square root of 999999859 is about 31622.7743722780. The cubic root of 999999859 is about 999.9999530000. Note that the first 4 decimals are identical.
The spelling of 999999859 in words is "nine hundred ninety-nine million, nine hundred ninety-nine thousand, eight hundred fifty-nine".