879991 has 6 divisors (see below), whose sum is σ = 1023720. Its totient is φ = 754236.

The previous prime is 879979. The next prime is 880001. The reversal of 879991 is 199978.

It is not a de Polignac number, because 879991 - 2⁷ = 879863 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (879941) 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, 8931 + ... + 9028.

It is an arithmetic number, because the mean of its divisors is an integer number (170620).

2⁸⁷⁹⁹⁹¹ is an apocalyptic number.

879991 is a deficient number, since it is larger than the sum of its proper divisors (143729).

879991 is a wasteful number, since it uses less digits than its factorization.

879991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17973 (or 17966 counting only the distinct ones).

The product of its digits is 40824, while the sum is 43.

The square root of 879991 is about 938.0783549363. The cubic root of 879991 is about 95.8280704524.

The spelling of 879991 in words is "eight hundred seventy-nine thousand, nine hundred ninety-one".