871989 has 4 divisors (see below), whose sum is σ = 1162656. Its totient is φ = 581324.

The previous prime is 871987. The next prime is 871993. The reversal of 871989 is 989178.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 871989 - 2¹ = 871987 is a prime.

It is a super-2 number, since 2×871989² = 1520729632242, which contains 22 as substring.

It is a D-number.

871989 is a lucky number.

It is a plaindrome in base 14 and base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 871989.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (871987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 145329 + ... + 145334.

It is an arithmetic number, because the mean of its divisors is an integer number (290664).

2⁸⁷¹⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

871989 is a deficient number, since it is larger than the sum of its proper divisors (290667).

871989 is a wasteful number, since it uses less digits than its factorization.

871989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290666.

The product of its digits is 36288, while the sum is 42.

The square root of 871989 is about 933.8035125228. The cubic root of 871989 is about 95.5367218956.

The spelling of 871989 in words is "eight hundred seventy-one thousand, nine hundred eighty-nine".