678856686523 has 2 divisors, whose sum is σ = 678856686524. Its totient is φ = 678856686522.

The previous prime is 678856686419. The next prime is 678856686527. The reversal of 678856686523 is 325686658876.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-678856686523 is a prime.

It is not a weakly prime, because it can be changed into another prime (678856686527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339428343261 + 339428343262.

It is an arithmetic number, because the mean of its divisors is an integer number (339428343262).

Almost surely, 2^678856686523 is an apocalyptic number.

678856686523 is a deficient number, since it is larger than the sum of its proper divisors (1).

678856686523 is an equidigital number, since it uses as much as digits as its factorization.

678856686523 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 696729600, while the sum is 70.

The spelling of 678856686523 in words is "six hundred seventy-eight billion, eight hundred fifty-six million, six hundred eighty-six thousand, five hundred twenty-three".