686773609 has 4 divisors (see below), whose sum is σ = 686850516. Its totient is φ = 686696704.

The previous prime is 686773589. The next prime is 686773627. The reversal of 686773609 is 906377686.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 906377686 = 2 ⋅453188843.

It can be written as a sum of positive squares in 2 ways, for example, as 271755225 + 415018384 = 16485^2 + 20372^2 .

It is a cyclic number.

It is not a de Polignac number, because 686773609 - 2⁹ = 686773097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (686773649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22984 + ... + 43609.

It is an arithmetic number, because the mean of its divisors is an integer number (171712629).

Almost surely, 2^686773609 is an apocalyptic number.

It is an amenable number.

686773609 is a deficient number, since it is larger than the sum of its proper divisors (76907).

686773609 is a wasteful number, since it uses less digits than its factorization.

686773609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76906.

The product of its (nonzero) digits is 2286144, while the sum is 52.

The square root of 686773609 is about 26206.3658106194. The cubic root of 686773609 is about 882.2761363227.

The spelling of 686773609 in words is "six hundred eighty-six million, seven hundred seventy-three thousand, six hundred nine".