861389 has 4 divisors (see below), whose sum is σ = 869856. Its totient is φ = 852924.

The previous prime is 861361. The next prime is 861391. The reversal of 861389 is 983168.

861389 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 a de Polignac number, because none of the positive numbers 2^k-861389 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 (861089) 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, 4079 + ... + 4284.

It is an arithmetic number, because the mean of its divisors is an integer number (217464).

2⁸⁶¹³⁸⁹ is an apocalyptic number.

It is an amenable number.

861389 is a deficient number, since it is larger than the sum of its proper divisors (8467).

861389 is a wasteful number, since it uses less digits than its factorization.

861389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8466.

The product of its digits is 10368, while the sum is 35.

The square root of 861389 is about 928.1104460138. The cubic root of 861389 is about 95.1480240844.

The spelling of 861389 in words is "eight hundred sixty-one thousand, three hundred eighty-nine".