686542849 has 2 divisors, whose sum is σ = 686542850. Its totient is φ = 686542848.

The previous prime is 686542783. The next prime is 686542891. The reversal of 686542849 is 948245686.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 402283249 + 284259600 = 20057^2 + 16860^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-686542849 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 686542796 and 686542805.

It is not a weakly prime, because it can be changed into another prime (686543849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343271424 + 343271425.

It is an arithmetic number, because the mean of its divisors is an integer number (343271425).

Almost surely, 2^686542849 is an apocalyptic number.

It is an amenable number.

686542849 is a deficient number, since it is larger than the sum of its proper divisors (1).

686542849 is an equidigital number, since it uses as much as digits as its factorization.

686542849 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3317760, while the sum is 52.

The square root of 686542849 is about 26201.9626936609. The cubic root of 686542849 is about 882.1773085840.

The spelling of 686542849 in words is "six hundred eighty-six million, five hundred forty-two thousand, eight hundred forty-nine".