686282809 has 27 divisors (see below), whose sum is σ = 773646447. Its totient is φ = 608608704.

The previous prime is 686282803. The next prime is 686282813. The reversal of 686282809 is 908282686.

The square root of 686282809 is 26197.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 534303225 + 151979584 = 23115^2 + 12328^2 .

It is not a de Polignac number, because 686282809 - 2¹⁵ = 686250041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (686282803) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 10242994 + ... + 10243060.

Almost surely, 2^686282809 is an apocalyptic number.

686282809 is the 26197-th square number.

686282809 is the 13099-th centered octagonal number.

It is an amenable number.

686282809 is a deficient number, since it is larger than the sum of its proper divisors (87363638).

686282809 is an equidigital number, since it uses as much as digits as its factorization.

686282809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214 (or 107 counting only the distinct ones).

The product of its (nonzero) digits is 663552, while the sum is 49.

The cubic root of 686282809 is about 882.0659145382.

Multiplying 686282809 by its sum of digits (49), we get a square (33627857641 = 183379²).

The spelling of 686282809 in words is "six hundred eighty-six million, two hundred eighty-two thousand, eight hundred nine".