78643393 has 2 divisors, whose sum is σ = 78643394. Its totient is φ = 78643392.

The previous prime is 78643379. The next prime is 78643507. The reversal of 78643393 is 39334687.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64112049 + 14531344 = 8007^2 + 3812^2 .

It is a cyclic number.

It is not a de Polignac number, because 78643393 - 2¹³ = 78635201 is a prime.

It is not a weakly prime, because it can be changed into another prime (78649393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39321696 + 39321697.

It is an arithmetic number, because the mean of its divisors is an integer number (39321697).

Almost surely, 2^78643393 is an apocalyptic number.

It is an amenable number.

78643393 is a deficient number, since it is larger than the sum of its proper divisors (1).

78643393 is an equidigital number, since it uses as much as digits as its factorization.

78643393 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 326592, while the sum is 43.

The square root of 78643393 is about 8868.1110164454. Note that the first 3 decimals coincide. The cubic root of 78643393 is about 428.4374385312.

The spelling of 78643393 in words is "seventy-eight million, six hundred forty-three thousand, three hundred ninety-three".