78928217 has 2 divisors, whose sum is σ = 78928218. Its totient is φ = 78928216.

The previous prime is 78928193. The next prime is 78928237. The reversal of 78928217 is 71282987.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72522256 + 6405961 = 8516^2 + 2531^2 .

It is an emirp because it is prime and its reverse (71282987) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78928217 - 2¹⁰ = 78927193 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (78928237) 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, 39464108 + 39464109.

It is an arithmetic number, because the mean of its divisors is an integer number (39464109).

Almost surely, 2^78928217 is an apocalyptic number.

It is an amenable number.

78928217 is a deficient number, since it is larger than the sum of its proper divisors (1).

78928217 is an equidigital number, since it uses as much as digits as its factorization.

78928217 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 112896, while the sum is 44.

The square root of 78928217 is about 8884.1553903565. The cubic root of 78928217 is about 428.9540415482.

The spelling of 78928217 in words is "seventy-eight million, nine hundred twenty-eight thousand, two hundred seventeen".