78822209 has 2 divisors, whose sum is σ = 78822210. Its totient is φ = 78822208.

The previous prime is 78822199. The next prime is 78822223. The reversal of 78822209 is 90222887.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 67699984 + 11122225 = 8228^2 + 3335^2 .

It is a cyclic number.

It is not a de Polignac number, because 78822209 - 2⁴ = 78822193 is a prime.

It is not a weakly prime, because it can be changed into another prime (78822229) 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, 39411104 + 39411105.

It is an arithmetic number, because the mean of its divisors is an integer number (39411105).

Almost surely, 2^78822209 is an apocalyptic number.

It is an amenable number.

78822209 is a deficient number, since it is larger than the sum of its proper divisors (1).

78822209 is an equidigital number, since it uses as much as digits as its factorization.

78822209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32256, while the sum is 38.

The square root of 78822209 is about 8878.1872586694. The cubic root of 78822209 is about 428.7619136674.

The spelling of 78822209 in words is "seventy-eight million, eight hundred twenty-two thousand, two hundred nine".