13781844 has 72 divisors (see below), whose sum is σ = 36996960. Its totient is φ = 4318272.

The previous prime is 13781843. The next prime is 13781861. The reversal of 13781844 is 44818731.

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

Its product of digits (21504) is a multiple of the sum of its prime divisors (384).

It is a junction number, because it is equal to n+sod(n) for n = 13781799 and 13781808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13781843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 44739 + ... + 45045.

Almost surely, 2^13781844 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 13781844, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18498480).

13781844 is an abundant number, since it is smaller than the sum of its proper divisors (23215116).

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

13781844 is a wasteful number, since it uses less digits than its factorization.

13781844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 389 (or 384 counting only the distinct ones).

The product of its digits is 21504, while the sum is 36.

The square root of 13781844 is about 3712.3906044488. The cubic root of 13781844 is about 239.7557932637.

The spelling of 13781844 in words is "thirteen million, seven hundred eighty-one thousand, eight hundred forty-four".