13781664 has 120 divisors (see below), whose sum is σ = 43756020. Its totient is φ = 4230144.

The previous prime is 13781653. The next prime is 13781681. The reversal of 13781664 is 46618731.

It can be written as a sum of positive squares in 2 ways, for example, as 13749264 + 32400 = 3708^2 + 180^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 33492 + ... + 33900.

Almost surely, 2^13781664 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 13781664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21878010).

13781664 is an abundant number, since it is smaller than the sum of its proper divisors (29974356).

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

13781664 is a wasteful number, since it uses less digits than its factorization.

13781664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 444 (or 427 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 13781664 is about 3712.3663612311. The cubic root of 13781664 is about 239.7547494694.

The spelling of 13781664 in words is "thirteen million, seven hundred eighty-one thousand, six hundred sixty-four".