686557349 has 2 divisors, whose sum is σ = 686557350. Its totient is φ = 686557348.

The previous prime is 686557327. The next prime is 686557351. The reversal of 686557349 is 943755686.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 527620900 + 158936449 = 22970^2 + 12607^2 .

It is a cyclic number.

It is not a de Polignac number, because 686557349 - 2¹² = 686553253 is a prime.

Together with 686557351, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 686557349.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (686557849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343278674 + 343278675.

It is an arithmetic number, because the mean of its divisors is an integer number (343278675).

Almost surely, 2^686557349 is an apocalyptic number.

It is an amenable number.

686557349 is a deficient number, since it is larger than the sum of its proper divisors (1).

686557349 is an equidigital number, since it uses as much as digits as its factorization.

686557349 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5443200, while the sum is 53.

The square root of 686557349 is about 26202.2393890293. The cubic root of 686557349 is about 882.1835191606.

The spelling of 686557349 in words is "six hundred eighty-six million, five hundred fifty-seven thousand, three hundred forty-nine".