686431 has 4 divisors (see below), whose sum is σ = 695200. Its totient is φ = 677664.

The previous prime is 686423. The next prime is 686437. The reversal of 686431 is 134686.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 134686 = 2 ⋅67343.

It is a cyclic number.

It is not a de Polignac number, because 686431 - 2³ = 686423 is a prime.

It is a super-2 number, since 2×686431² = 942375035522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 686431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686437) 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 3 ways as a sum of consecutive naturals, for example, 4266 + ... + 4423.

It is an arithmetic number, because the mean of its divisors is an integer number (173800).

2⁶⁸⁶⁴³¹ is an apocalyptic number.

686431 is a deficient number, since it is larger than the sum of its proper divisors (8769).

686431 is an equidigital number, since it uses as much as digits as its factorization.

686431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8768.

The product of its digits is 3456, while the sum is 28.

The square root of 686431 is about 828.5113155534. The cubic root of 686431 is about 88.2129398970.

It can be divided in two parts, 68643 and 1, that added together give a square (68644 = 262²).

The spelling of 686431 in words is "six hundred eighty-six thousand, four hundred thirty-one".