780864660 has 216 divisors, whose sum is σ = 2553727176. Its totient is φ = 193052160.

The previous prime is 780864607. The next prime is 780864661. The reversal of 780864660 is 66468087.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 87385104 + 693479556 = 9348^2 + 26334^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (780864661) by changing a digit.

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 71 ways as a sum of consecutive naturals, for example, 3963682 + ... + 3963878.

It is an arithmetic number, because the mean of its divisors is an integer number (11822811).

Almost surely, 2^780864660 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 780864660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1276863588).

780864660 is an abundant number, since it is smaller than the sum of its proper divisors (1772862516).

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

780864660 is a wasteful number, since it uses less digits than its factorization.

780864660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 311 (or 287 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 45.

The square root of 780864660 is about 27943.9556970734. The cubic root of 780864660 is about 920.8564252562.

The spelling of 780864660 in words is "seven hundred eighty million, eight hundred sixty-four thousand, six hundred sixty".