13209779981 has 2 divisors, whose sum is σ = 13209779982. Its totient is φ = 13209779980.

The previous prime is 13209779959. The next prime is 13209779983. The reversal of 13209779981 is 18997790231.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10975705225 + 2234074756 = 104765^2 + 47266^2 .

It is a cyclic number.

It is not a de Polignac number, because 13209779981 - 2¹⁴ = 13209763597 is a prime.

It is a super-2 number, since 2×13209779981² (a number of 21 digits) contains 22 as substring.

Together with 13209779983, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13209779983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6604889990 + 6604889991.

It is an arithmetic number, because the mean of its divisors is an integer number (6604889991).

Almost surely, 2^13209779981 is an apocalyptic number.

It is an amenable number.

13209779981 is a deficient number, since it is larger than the sum of its proper divisors (1).

13209779981 is an equidigital number, since it uses as much as digits as its factorization.

13209779981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1714608, while the sum is 56.

The spelling of 13209779981 in words is "thirteen billion, two hundred nine million, seven hundred seventy-nine thousand, nine hundred eighty-one".