78820261252861 has 2 divisors, whose sum is σ = 78820261252862. Its totient is φ = 78820261252860.

The previous prime is 78820261252729. The next prime is 78820261252879. The reversal of 78820261252861 is 16825216202887.

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., 68145338690361 + 10674922562500 = 8255019^2 + 3267250^2 .

It is a cyclic number.

It is not a de Polignac number, because 78820261252861 - 2⁹ = 78820261252349 is a prime.

It is a super-2 number, since 2×78820261252861² (a number of 29 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 78820261252796 and 78820261252805.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78820261252891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39410130626430 + 39410130626431.

It is an arithmetic number, because the mean of its divisors is an integer number (39410130626431).

Almost surely, 2^{78820261252861} is an apocalyptic number.

It is an amenable number.

78820261252861 is a deficient number, since it is larger than the sum of its proper divisors (1).

78820261252861 is an equidigital number, since it uses as much as digits as its factorization.

78820261252861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10321920, while the sum is 58.

The spelling of 78820261252861 in words is "seventy-eight trillion, eight hundred twenty billion, two hundred sixty-one million, two hundred fifty-two thousand, eight hundred sixty-one".