861679 has 16 divisors (see below), whose sum is σ = 1124928. Its totient is φ = 640512.

The previous prime is 861659. The next prime is 861691. The reversal of 861679 is 976168.

It is a cyclic number.

It is not a de Polignac number, because 861679 - 2⁵ = 861647 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1269 + ... + 1825.

It is an arithmetic number, because the mean of its divisors is an integer number (70308).

2⁸⁶¹⁶⁷⁹ is an apocalyptic number.

861679 is a deficient number, since it is larger than the sum of its proper divisors (263249).

861679 is a wasteful number, since it uses less digits than its factorization.

861679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 594.

The product of its digits is 18144, while the sum is 37.

The square root of 861679 is about 928.2666642727. The cubic root of 861679 is about 95.1587005736.

It can be divided in two parts, 861 and 679, that added together give a triangular number (1540 = T₅₅).

The spelling of 861679 in words is "eight hundred sixty-one thousand, six hundred seventy-nine".