13236781 has 2 divisors, whose sum is σ = 13236782. Its totient is φ = 13236780.

The previous prime is 13236779. The next prime is 13236791. The reversal of 13236781 is 18763231.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7155625 + 6081156 = 2675^2 + 2466^2 .

It is an emirp because it is prime and its reverse (18763231) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 13236781 - 2¹ = 13236779 is a prime.

It is a super-2 number, since 2×13236781² = 350424742483922, which contains 22 as substring.

Together with 13236779, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13236791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6618390 + 6618391.

It is an arithmetic number, because the mean of its divisors is an integer number (6618391).

Almost surely, 2^13236781 is an apocalyptic number.

It is an amenable number.

13236781 is a deficient number, since it is larger than the sum of its proper divisors (1).

13236781 is an equidigital number, since it uses as much as digits as its factorization.

13236781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6048, while the sum is 31.

The square root of 13236781 is about 3638.2387222391. The cubic root of 13236781 is about 236.5524558586.

The spelling of 13236781 in words is "thirteen million, two hundred thirty-six thousand, seven hundred eighty-one".