861791 has 4 divisors (see below), whose sum is σ = 984912. Its totient is φ = 738672.

The previous prime is 861761. The next prime is 861797. The reversal of 861791 is 197168.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-861791 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 (861797) 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, 61550 + ... + 61563.

It is an arithmetic number, because the mean of its divisors is an integer number (246228).

2⁸⁶¹⁷⁹¹ is an apocalyptic number.

861791 is a deficient number, since it is larger than the sum of its proper divisors (123121).

861791 is a wasteful number, since it uses less digits than its factorization.

861791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123120.

The product of its digits is 3024, while the sum is 32.

The square root of 861791 is about 928.3269898048. The cubic root of 861791 is about 95.1628232661.

The spelling of 861791 in words is "eight hundred sixty-one thousand, seven hundred ninety-one".