78428017 has 2 divisors, whose sum is σ = 78428018. Its totient is φ = 78428016.

The previous prime is 78427931. The next prime is 78428023. The reversal of 78428017 is 71082487.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 73119601 + 5308416 = 8551^2 + 2304^2 .

It is a cyclic number.

It is not a de Polignac number, because 78428017 - 2⁷ = 78427889 is a prime.

It is not a weakly prime, because it can be changed into another prime (78428027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39214008 + 39214009.

It is an arithmetic number, because the mean of its divisors is an integer number (39214009).

Almost surely, 2^78428017 is an apocalyptic number.

It is an amenable number.

78428017 is a deficient number, since it is larger than the sum of its proper divisors (1).

78428017 is an equidigital number, since it uses as much as digits as its factorization.

78428017 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25088, while the sum is 37.

The square root of 78428017 is about 8855.9594059594. The cubic root of 78428017 is about 428.0459688740.

The spelling of 78428017 in words is "seventy-eight million, four hundred twenty-eight thousand, seventeen".