781056 has 72 divisors (see below), whose sum is σ = 2330160. Its totient is φ = 258048.

The previous prime is 781051. The next prime is 781063. The reversal of 781056 is 650187.

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×781056² = 1220096950272, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (781051) by changing a digit.

781056 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6856 + ... + 6968.

2⁷⁸¹⁰⁵⁶ 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 781056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1165080).

781056 is an abundant number, since it is smaller than the sum of its proper divisors (1549104).

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

781056 is a wasteful number, since it uses less digits than its factorization.

781056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138 (or 118 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

The square root of 781056 is about 883.7737266971. The cubic root of 781056 is about 92.0931633457.

Subtracting from 781056 its product of nonzero digits (1680), we obtain a triangular number (779376 = T₁₂₄₈).

The spelling of 781056 in words is "seven hundred eighty-one thousand, fifty-six".