861279 has 4 divisors (see below), whose sum is σ = 1148376. Its totient is φ = 574184.

The previous prime is 861239. The next prime is 861293. The reversal of 861279 is 972168.

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-861279 is a prime.

It is a D-number.

861279 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861239) 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, 143544 + ... + 143549.

It is an arithmetic number, because the mean of its divisors is an integer number (287094).

2⁸⁶¹²⁷⁹ is an apocalyptic number.

861279 is a deficient number, since it is larger than the sum of its proper divisors (287097).

861279 is a wasteful number, since it uses less digits than its factorization.

861279 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287096.

The product of its digits is 6048, while the sum is 33.

The square root of 861279 is about 928.0511839333. The cubic root of 861279 is about 95.1439737547.

Subtracting 861279 from its reverse (972168), we obtain a square (110889 = 333²).

The spelling of 861279 in words is "eight hundred sixty-one thousand, two hundred seventy-nine".