781729680 has 160 divisors (see below), whose sum is σ = 2498411520. Its totient is φ = 202083840.

The previous prime is 781729643. The next prime is 781729721. The reversal of 781729680 is 86927187.

781729680 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×781729680² = 1222202585185804800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2177341 + ... + 2177699.

It is an arithmetic number, because the mean of its divisors is an integer number (15615072).

Almost surely, 2^781729680 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 781729680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1249205760).

781729680 is an abundant number, since it is smaller than the sum of its proper divisors (1716681840).

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

781729680 is a wasteful number, since it uses less digits than its factorization.

781729680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 629 (or 623 counting only the distinct ones).

The product of its (nonzero) digits is 338688, while the sum is 48.

The square root of 781729680 is about 27959.4291787225. The cubic root of 781729680 is about 921.1963327593.

The spelling of 781729680 in words is "seven hundred eighty-one million, seven hundred twenty-nine thousand, six hundred eighty".