78105025861 has 2 divisors, whose sum is σ = 78105025862. Its totient is φ = 78105025860.

The previous prime is 78105025841. The next prime is 78105025937. The reversal of 78105025861 is 16852050187.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 69857661636 + 8247364225 = 264306^2 + 90815^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78105025861 is a prime.

It is a super-2 number, since 2×78105025861² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78105025841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39052512930 + 39052512931.

It is an arithmetic number, because the mean of its divisors is an integer number (39052512931).

Almost surely, 2^78105025861 is an apocalyptic number.

It is an amenable number.

78105025861 is a deficient number, since it is larger than the sum of its proper divisors (1).

78105025861 is an equidigital number, since it uses as much as digits as its factorization.

78105025861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 134400, while the sum is 43.

The spelling of 78105025861 in words is "seventy-eight billion, one hundred five million, twenty-five thousand, eight hundred sixty-one".