779981561856 has 336 divisors, whose sum is σ = 2586117101568. Its totient is φ = 221891788800.

The previous prime is 779981561839. The next prime is 779981561893. The reversal of 779981561856 is 658165189977.

779981561856 is a `hidden beast` number, since 7 + 7 + 9 + 9 + 8 + 1 + 561 + 8 + 56 = 666.

It is a tau number, because it is divible by the number of its divisors (336).

It is a Harshad number since it is a multiple of its sum of digits (72).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 124376001 + ... + 124382271.

It is an arithmetic number, because the mean of its divisors is an integer number (7696777088).

Almost surely, 2^779981561856 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 779981561856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1293058550784).

779981561856 is an abundant number, since it is smaller than the sum of its proper divisors (1806135539712).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

779981561856 is a wasteful number, since it uses less digits than its factorization.

779981561856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6551 (or 6524 counting only the distinct ones).

The product of its digits is 228614400, while the sum is 72.

The spelling of 779981561856 in words is "seven hundred seventy-nine billion, nine hundred eighty-one million, five hundred sixty-one thousand, eight hundred fifty-six".