781328 has 20 divisors (see below), whose sum is σ = 1547520. Its totient is φ = 381984.

The previous prime is 781327. The next prime is 781351. The reversal of 781328 is 823187.

It is a super-2 number, since 2×781328² = 1220946887168, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 781328.

It is not an unprimeable number, because it can be changed into a prime (781321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 233 + ... + 1271.

It is an arithmetic number, because the mean of its divisors is an integer number (77376).

2⁷⁸¹³²⁸ is an apocalyptic number.

It is an amenable number.

781328 is a deficient number, since it is larger than the sum of its proper divisors (766192).

781328 is a wasteful number, since it uses less digits than its factorization.

781328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1094 (or 1088 counting only the distinct ones).

The product of its digits is 2688, while the sum is 29.

The square root of 781328 is about 883.9275988451. The cubic root of 781328 is about 92.1038524782.

The spelling of 781328 in words is "seven hundred eighty-one thousand, three hundred twenty-eight".