78218887666823 has 2 divisors, whose sum is σ = 78218887666824. Its totient is φ = 78218887666822.

The previous prime is 78218887666819. The next prime is 78218887666853. The reversal of 78218887666823 is 32866678881287.

It is a weak prime.

It is an emirp because it is prime and its reverse (32866678881287) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78218887666823 - 2² = 78218887666819 is a prime.

It is a super-2 number, since 2×78218887666823² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78218887666853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39109443833411 + 39109443833412.

It is an arithmetic number, because the mean of its divisors is an integer number (39109443833412).

Almost surely, 2^{78218887666823} is an apocalyptic number.

78218887666823 is a deficient number, since it is larger than the sum of its proper divisors (1).

78218887666823 is an equidigital number, since it uses as much as digits as its factorization.

78218887666823 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4161798144, while the sum is 80.

The spelling of 78218887666823 in words is "seventy-eight trillion, two hundred eighteen billion, eight hundred eighty-seven million, six hundred sixty-six thousand, eight hundred twenty-three".