691879 has 4 divisors (see below), whose sum is σ = 693576. Its totient is φ = 690184.

The previous prime is 691877. The next prime is 691891. The reversal of 691879 is 978196.

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

It is a cyclic number.

It is not a de Polignac number, because 691879 - 2¹ = 691877 is a prime.

It is a super-3 number, since 3×691879³ = 993600272282833317, which contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691871) 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, 177 + ... + 1189.

It is an arithmetic number, because the mean of its divisors is an integer number (173394).

2⁶⁹¹⁸⁷⁹ is an apocalyptic number.

691879 is a deficient number, since it is larger than the sum of its proper divisors (1697).

691879 is a wasteful number, since it uses less digits than its factorization.

691879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1696.

The product of its digits is 27216, while the sum is 40.

The square root of 691879 is about 831.7926424296. The cubic root of 691879 is about 88.4456985453.

It can be divided in two parts, 69187 and 9, that added together give a palindrome (69196).

The spelling of 691879 in words is "six hundred ninety-one thousand, eight hundred seventy-nine".