678706729 has 2 divisors, whose sum is σ = 678706730. Its totient is φ = 678706728.

The previous prime is 678706627. The next prime is 678706751. The reversal of 678706729 is 927607876.

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., 678706704 + 25 = 26052^2 + 5^2 .

It is a cyclic number.

It is not a de Polignac number, because 678706729 - 2¹⁹ = 678182441 is a prime.

It is not a weakly prime, because it can be changed into another prime (678706229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339353364 + 339353365.

It is an arithmetic number, because the mean of its divisors is an integer number (339353365).

Almost surely, 2^678706729 is an apocalyptic number.

It is an amenable number.

678706729 is a deficient number, since it is larger than the sum of its proper divisors (1).

678706729 is an equidigital number, since it uses as much as digits as its factorization.

678706729 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1778112, while the sum is 52.

The square root of 678706729 is about 26052.0004798096. Note that the first 3 decimals coincide. The cubic root of 678706729 is about 878.8081010020.

The spelling of 678706729 in words is "six hundred seventy-eight million, seven hundred six thousand, seven hundred twenty-nine".