859999 has 6 divisors (see below), whose sum is σ = 1000464. Its totient is φ = 737100.

The previous prime is 859987. The next prime is 860009. The reversal of 859999 is 999958.

859999 = T₂₆ + T₂₇ + ... + T₁₇₂.

It is not a de Polignac number, because 859999 - 2¹¹ = 857951 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49), and also a Moran number because the ratio is a prime number: 17551 = 859999 / (8 + 5 + 9 + 9 + 9 + 9).

It is a Duffinian number.

859999 is a modest number, since divided by 999 gives 859 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (859919) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8727 + ... + 8824.

It is an arithmetic number, because the mean of its divisors is an integer number (166744).

2⁸⁵⁹⁹⁹⁹ is an apocalyptic number.

859999 is a deficient number, since it is larger than the sum of its proper divisors (140465).

859999 is a wasteful number, since it uses less digits than its factorization.

859999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17565 (or 17558 counting only the distinct ones).

The product of its digits is 262440, while the sum is 49.

The square root of 859999 is about 927.3613103855. The cubic root of 859999 is about 95.0968172713.

The spelling of 859999 in words is "eight hundred fifty-nine thousand, nine hundred ninety-nine".