678138673 has 2 divisors, whose sum is σ = 678138674. Its totient is φ = 678138672.

The previous prime is 678138613. The next prime is 678138677. The reversal of 678138673 is 376831876.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 379782144 + 298356529 = 19488^2 + 17273^2 .

It is a cyclic number.

It is not a de Polignac number, because 678138673 - 2⁹ = 678138161 is a prime.

It is not a weakly prime, because it can be changed into another prime (678138677) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339069336 + 339069337.

It is an arithmetic number, because the mean of its divisors is an integer number (339069337).

Almost surely, 2^678138673 is an apocalyptic number.

It is an amenable number.

678138673 is a deficient number, since it is larger than the sum of its proper divisors (1).

678138673 is an equidigital number, since it uses as much as digits as its factorization.

678138673 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1016064, while the sum is 49.

The square root of 678138673 is about 26041.0958486773. The cubic root of 678138673 is about 878.5628544014.

It can be divided in two parts, 6781 and 38673, that added together give a palindrome (45454).

The spelling of 678138673 in words is "six hundred seventy-eight million, one hundred thirty-eight thousand, six hundred seventy-three".