778385664 has 324 divisors, whose sum is σ = 2740954944. Its totient is φ = 208060416.

The previous prime is 778385653. The next prime is 778385701. The reversal of 778385664 is 466583877.

778385664 is a `hidden beast` number, since 7 + 78 + 3 + 8 + 566 + 4 = 666.

Its product of digits (6773760) is a multiple of the sum of its prime divisors (196).

It is a self number, because there is not a number n which added to its sum of digits gives 778385664.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 4660909 + ... + 4661075.

Almost surely, 2^778385664 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 778385664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1370477472).

778385664 is an abundant number, since it is smaller than the sum of its proper divisors (1962569280).

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

778385664 is a wasteful number, since it uses less digits than its factorization.

778385664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230 (or 196 counting only the distinct ones).

The product of its digits is 6773760, while the sum is 54.

The square root of 778385664 is about 27899.5638675589. The cubic root of 778385664 is about 919.8809171640.

The spelling of 778385664 in words is "seven hundred seventy-eight million, three hundred eighty-five thousand, six hundred sixty-four".