678456109 has 2 divisors, whose sum is σ = 678456110. Its totient is φ = 678456108.

The previous prime is 678456089. The next prime is 678456133. The reversal of 678456109 is 901654876.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 648720900 + 29735209 = 25470^2 + 5453^2 .

It is a cyclic number.

It is not a de Polignac number, because 678456109 - 2²⁷ = 544238381 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (678456169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339228054 + 339228055.

It is an arithmetic number, because the mean of its divisors is an integer number (339228055).

Almost surely, 2^678456109 is an apocalyptic number.

It is an amenable number.

678456109 is a deficient number, since it is larger than the sum of its proper divisors (1).

678456109 is an equidigital number, since it uses as much as digits as its factorization.

678456109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 362880, while the sum is 46.

The square root of 678456109 is about 26047.1900403863. The cubic root of 678456109 is about 878.6999178001.

The spelling of 678456109 in words is "six hundred seventy-eight million, four hundred fifty-six thousand, one hundred nine".