78678989 has 2 divisors, whose sum is σ = 78678990. Its totient is φ = 78678988.

The previous prime is 78678973. The next prime is 78679033. The reversal of 78678989 is 98987687.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 46812964 + 31866025 = 6842^2 + 5645^2 .

It is a cyclic number.

It is not a de Polignac number, because 78678989 - 2⁴ = 78678973 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78678289) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39339494 + 39339495.

It is an arithmetic number, because the mean of its divisors is an integer number (39339495).

Almost surely, 2^78678989 is an apocalyptic number.

It is an amenable number.

78678989 is a deficient number, since it is larger than the sum of its proper divisors (1).

78678989 is an equidigital number, since it uses as much as digits as its factorization.

78678989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12192768, while the sum is 62.

The square root of 78678989 is about 8870.1177557009. The cubic root of 78678989 is about 428.5020693418.

The spelling of 78678989 in words is "seventy-eight million, six hundred seventy-eight thousand, nine hundred eighty-nine".