861889 has 4 divisors (see below), whose sum is σ = 985024. Its totient is φ = 738756.

The previous prime is 861881. The next prime is 861899. The reversal of 861889 is 988168.

It is a happy number.

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 861889 - 2³ = 861881 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 (861881) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61557 + ... + 61570.

It is an arithmetic number, because the mean of its divisors is an integer number (246256).

2⁸⁶¹⁸⁸⁹ is an apocalyptic number.

It is an amenable number.

861889 is a deficient number, since it is larger than the sum of its proper divisors (123135).

861889 is a wasteful number, since it uses less digits than its factorization.

861889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123134.

The product of its digits is 27648, while the sum is 40.

The square root of 861889 is about 928.3797714298. The cubic root of 861889 is about 95.1664303291.

The spelling of 861889 in words is "eight hundred sixty-one thousand, eight hundred eighty-nine".