77968861 has 2 divisors, whose sum is σ = 77968862. Its totient is φ = 77968860.

The previous prime is 77968859. The next prime is 77968889. The reversal of 77968861 is 16886977.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 62805625 + 15163236 = 7925^2 + 3894^2 .

It is an emirp because it is prime and its reverse (16886977) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77968861 - 2¹ = 77968859 is a prime.

Together with 77968859, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 77968799 and 77968808.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77968801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38984430 + 38984431.

It is an arithmetic number, because the mean of its divisors is an integer number (38984431).

Almost surely, 2^77968861 is an apocalyptic number.

It is an amenable number.

77968861 is a deficient number, since it is larger than the sum of its proper divisors (1).

77968861 is an equidigital number, since it uses as much as digits as its factorization.

77968861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1016064, while the sum is 52.

The square root of 77968861 is about 8829.9977916192. The cubic root of 77968861 is about 427.2090032008.

The spelling of 77968861 in words is "seventy-seven million, nine hundred sixty-eight thousand, eight hundred sixty-one".