784641640 has 72 divisors (see below), whose sum is σ = 1825173810. Its totient is φ = 303581376.

The previous prime is 784641631. The next prime is 784641643. The reversal of 784641640 is 46146487.

784641640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 706177476 + 78464164 = 26574^2 + 8858^2 .

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 784641593 and 784641602.

It is not an unprimeable number, because it can be changed into a prime (784641643) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 7617829 + ... + 7617931.

Almost surely, 2^784641640 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 784641640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (912586905).

784641640 is an abundant number, since it is smaller than the sum of its proper divisors (1040532170).

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

784641640 is a wasteful number, since it uses less digits than its factorization.

784641640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303 (or 153 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 40.

The square root of 784641640 is about 28011.4555137715. The cubic root of 784641640 is about 922.3387408677.

Multiplying 784641640 by its sum of digits (40), we get a square (31385665600 = 177160²).

784641640 divided by its sum of digits (40) gives a square (19616041 = 4429²).

The spelling of 784641640 in words is "seven hundred eighty-four million, six hundred forty-one thousand, six hundred forty".