78866393 has 2 divisors, whose sum is σ = 78866394. Its totient is φ = 78866392.

The previous prime is 78866369. The next prime is 78866413. The reversal of 78866393 is 39366887.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77492809 + 1373584 = 8803^2 + 1172^2 .

It is a cyclic number.

It is not a de Polignac number, because 78866393 - 2²² = 74672089 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (78866363) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39433196 + 39433197.

It is an arithmetic number, because the mean of its divisors is an integer number (39433197).

Almost surely, 2^78866393 is an apocalyptic number.

It is an amenable number.

78866393 is a deficient number, since it is larger than the sum of its proper divisors (1).

78866393 is an equidigital number, since it uses as much as digits as its factorization.

78866393 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1306368, while the sum is 50.

The square root of 78866393 is about 8880.6752558575. The cubic root of 78866393 is about 428.8420132482.

The spelling of 78866393 in words is "seventy-eight million, eight hundred sixty-six thousand, three hundred ninety-three".