78121789900841 has 2 divisors, whose sum is σ = 78121789900842. Its totient is φ = 78121789900840.

The previous prime is 78121789900831. The next prime is 78121789900849. The reversal of 78121789900841 is 14800998712187.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 58023640155625 + 20098149745216 = 7617325^2 + 4483096^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78121789900841 is a prime.

It is a super-2 number, since 2×78121789900841² (a number of 29 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78121789900849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39060894950420 + 39060894950421.

It is an arithmetic number, because the mean of its divisors is an integer number (39060894950421).

Almost surely, 2^{78121789900841} is an apocalyptic number.

It is an amenable number.

78121789900841 is a deficient number, since it is larger than the sum of its proper divisors (1).

78121789900841 is an equidigital number, since it uses as much as digits as its factorization.

78121789900841 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16257024, while the sum is 65.

The spelling of 78121789900841 in words is "seventy-eight trillion, one hundred twenty-one billion, seven hundred eighty-nine million, nine hundred thousand, eight hundred forty-one".