678907891 has 2 divisors, whose sum is σ = 678907892. Its totient is φ = 678907890.

The previous prime is 678907861. The next prime is 678907919. The reversal of 678907891 is 198709876.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 678907891 - 2⁹ = 678907379 is a prime.

It is not a weakly prime, because it can be changed into another prime (678907861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339453945 + 339453946.

It is an arithmetic number, because the mean of its divisors is an integer number (339453946).

Almost surely, 2^678907891 is an apocalyptic number.

678907891 is a deficient number, since it is larger than the sum of its proper divisors (1).

678907891 is an equidigital number, since it uses as much as digits as its factorization.

678907891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1524096, while the sum is 55.

The square root of 678907891 is about 26055.8609721498. The cubic root of 678907891 is about 878.8949157852.

The spelling of 678907891 in words is "six hundred seventy-eight million, nine hundred seven thousand, eight hundred ninety-one".