78856321 has 2 divisors, whose sum is σ = 78856322. Its totient is φ = 78856320.

The previous prime is 78856199. The next prime is 78856331. The reversal of 78856321 is 12365887.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69639025 + 9217296 = 8345^2 + 3036^2 .

It is a cyclic number.

It is not a de Polignac number, because 78856321 - 2²¹ = 76759169 is a prime.

It is not a weakly prime, because it can be changed into another prime (78856331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39428160 + 39428161.

It is an arithmetic number, because the mean of its divisors is an integer number (39428161).

Almost surely, 2^78856321 is an apocalyptic number.

It is an amenable number.

78856321 is a deficient number, since it is larger than the sum of its proper divisors (1).

78856321 is an equidigital number, since it uses as much as digits as its factorization.

78856321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 80640, while the sum is 40.

The square root of 78856321 is about 8880.1081637557. The cubic root of 78856321 is about 428.8237567156.

The spelling of 78856321 in words is "seventy-eight million, eight hundred fifty-six thousand, three hundred twenty-one".