999999858 has 64 divisors (see below), whose sum is σ = 2363582592. Its totient is φ = 278062080.

The previous prime is 999999797. The next prime is 999999883. The reversal of 999999858 is 858999999.

It is a self number, because there is not a number n which added to its sum of digits gives 999999858.

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 31 ways as a sum of consecutive naturals, for example, 145066 + ... + 151802.

It is an arithmetic number, because the mean of its divisors is an integer number (36930978).

Almost surely, 2^999999858 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 999999858, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1181791296).

999999858 is an abundant number, since it is smaller than the sum of its proper divisors (1363582734).

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

999999858 is a wasteful number, since it uses less digits than its factorization.

999999858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6939.

The product of its digits is 170061120, while the sum is 75.

The square root of 999999858 is about 31622.7743564666. The cubic root of 999999858 is about 999.9999526667. Note that the first 4 decimals are identical.

The spelling of 999999858 in words is "nine hundred ninety-nine million, nine hundred ninety-nine thousand, eight hundred fifty-eight".