13661281 has 2 divisors, whose sum is σ = 13661282. Its totient is φ = 13661280.

The previous prime is 13661279. The next prime is 13661303. The reversal of 13661281 is 18216631.

13661281 is digitally balanced in base 3, because in such base 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., 9000000 + 4661281 = 3000^2 + 2159^2 .

It is a cyclic number.

It is not a de Polignac number, because 13661281 - 2¹ = 13661279 is a prime.

It is a super-2 number, since 2×13661281² = 373261197121922, which contains 22 as substring.

Together with 13661279, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (13661201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6830640 + 6830641.

It is an arithmetic number, because the mean of its divisors is an integer number (6830641).

Almost surely, 2^13661281 is an apocalyptic number.

It is an amenable number.

13661281 is a deficient number, since it is larger than the sum of its proper divisors (1).

13661281 is an equidigital number, since it uses as much as digits as its factorization.

13661281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 28.

The square root of 13661281 is about 3696.1170165459. The cubic root of 13661281 is about 239.0546200800.

The spelling of 13661281 in words is "thirteen million, six hundred sixty-one thousand, two hundred eighty-one".