686704189 has 2 divisors, whose sum is σ = 686704190. Its totient is φ = 686704188.

The previous prime is 686704181. The next prime is 686704231. The reversal of 686704189 is 981407686.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 666156100 + 20548089 = 25810^2 + 4533^2 .

It is a cyclic number.

It is not a de Polignac number, because 686704189 - 2³ = 686704181 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (686704181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343352094 + 343352095.

It is an arithmetic number, because the mean of its divisors is an integer number (343352095).

Almost surely, 2^686704189 is an apocalyptic number.

It is an amenable number.

686704189 is a deficient number, since it is larger than the sum of its proper divisors (1).

686704189 is an equidigital number, since it uses as much as digits as its factorization.

686704189 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 580608, while the sum is 49.

The square root of 686704189 is about 26205.0412897977. The cubic root of 686704189 is about 882.2464081016.

The spelling of 686704189 in words is "six hundred eighty-six million, seven hundred four thousand, one hundred eighty-nine".