859991 has 8 divisors (see below), whose sum is σ = 963984. Its totient is φ = 760320.

The previous prime is 859987. The next prime is 860009. The reversal of 859991 is 199958.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 859991 - 2² = 859987 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 859991.

It is not an unprimeable number, because it can be changed into a prime (859981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 650 + ... + 1463.

It is an arithmetic number, because the mean of its divisors is an integer number (120498).

2⁸⁵⁹⁹⁹¹ is an apocalyptic number.

859991 is a deficient number, since it is larger than the sum of its proper divisors (103993).

859991 is a wasteful number, since it uses less digits than its factorization.

859991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2161.

The product of its digits is 29160, while the sum is 41.

The square root of 859991 is about 927.3569970621. The cubic root of 859991 is about 95.0965223962.

The spelling of 859991 in words is "eight hundred fifty-nine thousand, nine hundred ninety-one".