678887749 has 2 divisors, whose sum is σ = 678887750. Its totient is φ = 678887748.

The previous prime is 678887743. The next prime is 678887773. The reversal of 678887749 is 947788876.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 405216900 + 273670849 = 20130^2 + 16543^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-678887749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (678887743) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339443874 + 339443875.

It is an arithmetic number, because the mean of its divisors is an integer number (339443875).

Almost surely, 2^678887749 is an apocalyptic number.

It is an amenable number.

678887749 is a deficient number, since it is larger than the sum of its proper divisors (1).

678887749 is an equidigital number, since it uses as much as digits as its factorization.

678887749 is an evil number, because the sum of its binary digits is even.

The product of its digits is 37933056, while the sum is 64.

The square root of 678887749 is about 26055.4744535577. The cubic root of 678887749 is about 878.8862239451.

The spelling of 678887749 in words is "six hundred seventy-eight million, eight hundred eighty-seven thousand, seven hundred forty-nine".