13788781 has 2 divisors, whose sum is σ = 13788782. Its totient is φ = 13788780.

The previous prime is 13788779. The next prime is 13788787. The reversal of 13788781 is 18788731.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11115556 + 2673225 = 3334^2 + 1635^2 .

It is a cyclic number.

It is not a de Polignac number, because 13788781 - 2¹ = 13788779 is a prime.

It is a super-2 number, since 2×13788781² = 380260962931922, which contains 22 as substring.

Together with 13788779, 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 (13788787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6894390 + 6894391.

It is an arithmetic number, because the mean of its divisors is an integer number (6894391).

Almost surely, 2^13788781 is an apocalyptic number.

It is an amenable number.

13788781 is a deficient number, since it is larger than the sum of its proper divisors (1).

13788781 is an equidigital number, since it uses as much as digits as its factorization.

13788781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 75264, while the sum is 43.

The square root of 13788781 is about 3713.3247905348. The cubic root of 13788781 is about 239.7960130138.

The spelling of 13788781 in words is "thirteen million, seven hundred eighty-eight thousand, seven hundred eighty-one".