78326861 has 2 divisors, whose sum is σ = 78326862. Its totient is φ = 78326860.

The previous prime is 78326849. The next prime is 78326881. The reversal of 78326861 is 16862387.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 57851236 + 20475625 = 7606^2 + 4525^2 .

It is an emirp because it is prime and its reverse (16862387) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78326861 is a prime.

It is a super-2 number, since 2×78326861² = 12270194308226642, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78326881) 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, 39163430 + 39163431.

It is an arithmetic number, because the mean of its divisors is an integer number (39163431).

Almost surely, 2^78326861 is an apocalyptic number.

It is an amenable number.

78326861 is a deficient number, since it is larger than the sum of its proper divisors (1).

78326861 is an equidigital number, since it uses as much as digits as its factorization.

78326861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96768, while the sum is 41.

The square root of 78326861 is about 8850.2463807512. The cubic root of 78326861 is about 427.8618592968.

The spelling of 78326861 in words is "seventy-eight million, three hundred twenty-six thousand, eight hundred sixty-one".