13205981 has 2 divisors, whose sum is σ = 13205982. Its totient is φ = 13205980.

The previous prime is 13205953. The next prime is 13205987. The reversal of 13205981 is 18950231.

13205981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13205956 + 25 = 3634^2 + 5^2 .

It is an emirp because it is prime and its reverse (18950231) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 13205981 - 2¹⁰ = 13204957 is a prime.

It is a super-2 number, since 2×13205981² = 348795868344722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13205987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6602990 + 6602991.

It is an arithmetic number, because the mean of its divisors is an integer number (6602991).

Almost surely, 2^13205981 is an apocalyptic number.

It is an amenable number.

13205981 is a deficient number, since it is larger than the sum of its proper divisors (1).

13205981 is an equidigital number, since it uses as much as digits as its factorization.

13205981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 13205981 is about 3634.0034397342. The cubic root of 13205981 is about 236.3688393646.

The spelling of 13205981 in words is "thirteen million, two hundred five thousand, nine hundred eighty-one".