686710680221 has 4 divisors (see below), whose sum is σ = 703459721244. Its totient is φ = 669961639200.

The previous prime is 686710680193. The next prime is 686710680233. The reversal of 686710680221 is 122086017686.

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

It can be written as a sum of positive squares in 2 ways, for example, as 30628500100 + 656082180121 = 175010^2 + 809989^2 .

It is a cyclic number.

It is not a de Polignac number, because 686710680221 - 2⁶ = 686710680157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686710680281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8374520450 + ... + 8374520531.

It is an arithmetic number, because the mean of its divisors is an integer number (175864930311).

Almost surely, 2^686710680221 is an apocalyptic number.

It is an amenable number.

686710680221 is a deficient number, since it is larger than the sum of its proper divisors (16749041023).

686710680221 is a wasteful number, since it uses less digits than its factorization.

686710680221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16749041022.

The product of its (nonzero) digits is 387072, while the sum is 47.

The spelling of 686710680221 in words is "six hundred eighty-six billion, seven hundred ten million, six hundred eighty thousand, two hundred twenty-one".