686261 has 6 divisors (see below), whose sum is σ = 724662. Its totient is φ = 649800.

The previous prime is 686209. The next prime is 686267. The reversal of 686261 is 162686.

It can be written as a sum of positive squares in only one way, i.e., 442225 + 244036 = 665^2 + 494^2 .

It is not a de Polignac number, because 686261 - 2⁶ = 686197 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 7.

It is a zygodrome in base 7.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686267) 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 5 ways as a sum of consecutive naturals, for example, 590 + ... + 1311.

It is an arithmetic number, because the mean of its divisors is an integer number (120777).

2⁶⁸⁶²⁶¹ is an apocalyptic number.

It is an amenable number.

686261 is a deficient number, since it is larger than the sum of its proper divisors (38401).

686261 is a wasteful number, since it uses less digits than its factorization.

686261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1939 (or 1920 counting only the distinct ones).

The product of its digits is 3456, while the sum is 29.

The square root of 686261 is about 828.4087155505. The cubic root of 686261 is about 88.2056570878.

The spelling of 686261 in words is "six hundred eighty-six thousand, two hundred sixty-one".