12781944 has 72 divisors (see below), whose sum is σ = 40280760. Its totient is φ = 3650976.

The previous prime is 12781939. The next prime is 12782009. The reversal of 12781944 is 44918721.

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

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 12781899 and 12781908.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1717 + ... + 5339.

It is an arithmetic number, because the mean of its divisors is an integer number (559455).

Almost surely, 2^12781944 is an apocalyptic number.

12781944 is a gapful number since it is divisible by the number (14) 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 12781944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20140380).

12781944 is an abundant number, since it is smaller than the sum of its proper divisors (27498816).

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

12781944 is a wasteful number, since it uses less digits than its factorization.

12781944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3649 (or 3635 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 12781944 is about 3575.1844707651. The cubic root of 12781944 is about 233.8113754968.

The spelling of 12781944 in words is "twelve million, seven hundred eighty-one thousand, nine hundred forty-four".