678065209 has 2 divisors, whose sum is σ = 678065210. Its totient is φ = 678065208.

The previous prime is 678065189. The next prime is 678065239. The reversal of 678065209 is 902560876.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 365765625 + 312299584 = 19125^2 + 17672^2 .

It is a cyclic number.

It is not a de Polignac number, because 678065209 - 2²¹ = 675968057 is a prime.

It is not a weakly prime, because it can be changed into another prime (678065239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339032604 + 339032605.

It is an arithmetic number, because the mean of its divisors is an integer number (339032605).

Almost surely, 2^678065209 is an apocalyptic number.

It is an amenable number.

678065209 is a deficient number, since it is larger than the sum of its proper divisors (1).

678065209 is an equidigital number, since it uses as much as digits as its factorization.

678065209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 181440, while the sum is 43.

The square root of 678065209 is about 26039.6852707555. The cubic root of 678065209 is about 878.5311278166.

The spelling of 678065209 in words is "six hundred seventy-eight million, sixty-five thousand, two hundred nine".