13644981 has 18 divisors (see below), whose sum is σ = 22928022. Its totient is φ = 7796880.

The previous prime is 13644979. The next prime is 13644997. The reversal of 13644981 is 18944631.

13644981 is a `hidden beast` number, since 1 + 3 + 644 + 9 + 8 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 10458756 + 3186225 = 3234^2 + 1785^2 .

It is not a de Polignac number, because 13644981 - 2¹ = 13644979 is a prime.

It is a super-2 number, since 2×13644981² = 372371012980722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13644581) 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 17 ways as a sum of consecutive naturals, for example, 15030 + ... + 15911.

It is an arithmetic number, because the mean of its divisors is an integer number (1273779).

Almost surely, 2^13644981 is an apocalyptic number.

It is an amenable number.

13644981 is a deficient number, since it is larger than the sum of its proper divisors (9283041).

13644981 is a wasteful number, since it uses less digits than its factorization.

13644981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30961 (or 30951 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 13644981 is about 3693.9113416540. The cubic root of 13644981 is about 238.9595059864.

The spelling of 13644981 in words is "thirteen million, six hundred forty-four thousand, nine hundred eighty-one".