686000221 has 2 divisors, whose sum is σ = 686000222. Its totient is φ = 686000220.

The previous prime is 686000197. The next prime is 686000251. The reversal of 686000221 is 122000686.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 676728196 + 9272025 = 26014^2 + 3045^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-686000221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (686000251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343000110 + 343000111.

It is an arithmetic number, because the mean of its divisors is an integer number (343000111).

Almost surely, 2^686000221 is an apocalyptic number.

It is an amenable number.

686000221 is a deficient number, since it is larger than the sum of its proper divisors (1).

686000221 is an equidigital number, since it uses as much as digits as its factorization.

686000221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 686000221 is about 26191.6059263269. The cubic root of 686000221 is about 881.9448296348.

The spelling of 686000221 in words is "six hundred eighty-six million, two hundred twenty-one", and thus it is an aban number.