78243017 has 2 divisors, whose sum is σ = 78243018. Its totient is φ = 78243016.

The previous prime is 78242981. The next prime is 78243037. The reversal of 78243017 is 71034287.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52649536 + 25593481 = 7256^2 + 5059^2 .

It is an emirp because it is prime and its reverse (71034287) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78243017 - 2⁶ = 78242953 is a prime.

It is a super-2 number, since 2×78243017² = 12243939418524578, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (78243037) 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, 39121508 + 39121509.

It is an arithmetic number, because the mean of its divisors is an integer number (39121509).

Almost surely, 2^78243017 is an apocalyptic number.

It is an amenable number.

78243017 is a deficient number, since it is larger than the sum of its proper divisors (1).

78243017 is an equidigital number, since it uses as much as digits as its factorization.

78243017 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9408, while the sum is 32.

The square root of 78243017 is about 8845.5082951744. The cubic root of 78243017 is about 427.7091383483.

The spelling of 78243017 in words is "seventy-eight million, two hundred forty-three thousand, seventeen".