686678249 has 2 divisors, whose sum is σ = 686678250. Its totient is φ = 686678248.

The previous prime is 686678197. The next prime is 686678299. The reversal of 686678249 is 942876686.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 529000000 + 157678249 = 23000^2 + 12557^2 .

It is a cyclic number.

It is not a de Polignac number, because 686678249 - 2¹⁶ = 686612713 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 686678194 and 686678203.

It is not a weakly prime, because it can be changed into another prime (686678299) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343339124 + 343339125.

It is an arithmetic number, because the mean of its divisors is an integer number (343339125).

Almost surely, 2^686678249 is an apocalyptic number.

It is an amenable number.

686678249 is a deficient number, since it is larger than the sum of its proper divisors (1).

686678249 is an equidigital number, since it uses as much as digits as its factorization.

686678249 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6967296, while the sum is 56.

The square root of 686678249 is about 26204.5463421903. The cubic root of 686678249 is about 882.2352991164.

The spelling of 686678249 in words is "six hundred eighty-six million, six hundred seventy-eight thousand, two hundred forty-nine".