781320 has 64 divisors (see below), whose sum is σ = 2488320. Its totient is φ = 195584.

The previous prime is 781309. The next prime is 781321. The reversal of 781320 is 23187.

It is a super-2 number, since 2×781320² = 1220921884800, which contains 22 as substring.

It is a congruent number.

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

781320 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 15 ways as a sum of consecutive naturals, for example, 1849 + ... + 2231.

It is an arithmetic number, because the mean of its divisors is an integer number (38880).

2⁷⁸¹³²⁰ 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 781320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1244160).

781320 is an abundant number, since it is smaller than the sum of its proper divisors (1707000).

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

781320 is a wasteful number, since it uses less digits than its factorization.

781320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 414 (or 410 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 21.

The square root of 781320 is about 883.9230735760. The cubic root of 781320 is about 92.1035381274.

The spelling of 781320 in words is "seven hundred eighty-one thousand, three hundred twenty".