13663681 has 2 divisors, whose sum is σ = 13663682. Its totient is φ = 13663680.

The previous prime is 13663673. The next prime is 13663691. The reversal of 13663681 is 18636631.

It is a happy number.

13663681 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7612081 + 6051600 = 2759^2 + 2460^2 .

It is a cyclic number.

It is not a de Polignac number, because 13663681 - 2³ = 13663673 is a prime.

It is a super-2 number, since 2×13663681² = 373392356939522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (13663691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6831840 + 6831841.

It is an arithmetic number, because the mean of its divisors is an integer number (6831841).

Almost surely, 2^13663681 is an apocalyptic number.

It is an amenable number.

13663681 is a deficient number, since it is larger than the sum of its proper divisors (1).

13663681 is an equidigital number, since it uses as much as digits as its factorization.

13663681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15552, while the sum is 34.

The square root of 13663681 is about 3696.4416673336. The cubic root of 13663681 is about 239.0686182181.

The spelling of 13663681 in words is "thirteen million, six hundred sixty-three thousand, six hundred eighty-one".