12781720 has 64 divisors (see below), whose sum is σ = 33177600. Its totient is φ = 4341120.

The previous prime is 12781669. The next prime is 12781723. The reversal of 12781720 is 2718721.

It is a super-3 number, since 3×12781720³ (a number of 22 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12781723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53361 + ... + 53599.

It is an arithmetic number, because the mean of its divisors is an integer number (518400).

Almost surely, 2^12781720 is an apocalyptic number.

12781720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 12781720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16588800).

12781720 is an abundant number, since it is smaller than the sum of its proper divisors (20395880).

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

12781720 is a wasteful number, since it uses less digits than its factorization.

12781720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 448 (or 444 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 28.

The square root of 12781720 is about 3575.1531435730. The cubic root of 12781720 is about 233.8100096625.

12781720 divided by its sum of digits (28) gives a triangular number (456490 = T₉₅₅).

The spelling of 12781720 in words is "twelve million, seven hundred eighty-one thousand, seven hundred twenty".