781677320969 has 2 divisors, whose sum is σ = 781677320970. Its totient is φ = 781677320968.

The previous prime is 781677320959. The next prime is 781677321013. The reversal of 781677320969 is 969023776187.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 687551080969 + 94126240000 = 829187^2 + 306800^2 .

It is an emirp because it is prime and its reverse (969023776187) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 781677320969 - 2²⁰ = 781676272393 is a prime.

It is a super-2 number, since 2×781677320969² (a number of 25 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (781677320959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390838660484 + 390838660485.

It is an arithmetic number, because the mean of its divisors is an integer number (390838660485).

Almost surely, 2^781677320969 is an apocalyptic number.

It is an amenable number.

781677320969 is a deficient number, since it is larger than the sum of its proper divisors (1).

781677320969 is an equidigital number, since it uses as much as digits as its factorization.

781677320969 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48009024, while the sum is 65.

The spelling of 781677320969 in words is "seven hundred eighty-one billion, six hundred seventy-seven million, three hundred twenty thousand, nine hundred sixty-nine".