78889009 has 2 divisors, whose sum is σ = 78889010. Its totient is φ = 78889008.

The previous prime is 78888991. The next prime is 78889037. The reversal of 78889009 is 90098887.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 67699984 + 11189025 = 8228^2 + 3345^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78889009 is a prime.

It is not a weakly prime, because it can be changed into another prime (78881009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39444504 + 39444505.

It is an arithmetic number, because the mean of its divisors is an integer number (39444505).

Almost surely, 2^78889009 is an apocalyptic number.

It is an amenable number.

78889009 is a deficient number, since it is larger than the sum of its proper divisors (1).

78889009 is an equidigital number, since it uses as much as digits as its factorization.

78889009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 290304, while the sum is 49.

The square root of 78889009 is about 8881.9484911814. The cubic root of 78889009 is about 428.8830014042.

The spelling of 78889009 in words is "seventy-eight million, eight hundred eighty-nine thousand, nine".