784685664 has 192 divisors, whose sum is σ = 2729825280. Its totient is φ = 214410240.

The previous prime is 784685653. The next prime is 784685669. The reversal of 784685664 is 466586487.

784685664 is a `hidden beast` number, since 78 + 4 + 6 + 8 + 566 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 784685664.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (784685669) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 136284 + ... + 141924.

It is an arithmetic number, because the mean of its divisors is an integer number (14217840).

Almost surely, 2^784685664 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 784685664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1364912640).

784685664 is an abundant number, since it is smaller than the sum of its proper divisors (1945139616).

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

784685664 is a wasteful number, since it uses less digits than its factorization.

784685664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5690 (or 5676 counting only the distinct ones).

The product of its digits is 7741440, while the sum is 54.

The square root of 784685664 is about 28012.2413241069. The cubic root of 784685664 is about 922.3559904754.

The spelling of 784685664 in words is "seven hundred eighty-four million, six hundred eighty-five thousand, six hundred sixty-four".