999999859 has 4 divisors (see below), whose sum is σ = 1000064016. Its totient is φ = 999935704.

The previous prime is 999999797. The next prime is 999999883. The reversal of 999999859 is 958999999.

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 not a de Polignac number, because 999999859 - 2¹¹ = 999997811 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (999999059) 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, 7962 + ... + 45424.

It is an arithmetic number, because the mean of its divisors is an integer number (250016004).

Almost surely, 2^999999859 is an apocalyptic number.

999999859 is a deficient number, since it is larger than the sum of its proper divisors (64157).

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 product of its digits is 191318760, while the sum is 76.

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".