13778917 has 2 divisors, whose sum is σ = 13778918. Its totient is φ = 13778916.

The previous prime is 13778903. The next prime is 13778923. The reversal of 13778917 is 71987731.

13778917 is digitally balanced in base 3, 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., 13771521 + 7396 = 3711^2 + 86^2 .

It is an emirp because it is prime and its reverse (71987731) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13778917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13778927) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6889458 + 6889459.

It is an arithmetic number, because the mean of its divisors is an integer number (6889459).

Almost surely, 2^13778917 is an apocalyptic number.

It is an amenable number.

13778917 is a deficient number, since it is larger than the sum of its proper divisors (1).

13778917 is an equidigital number, since it uses as much as digits as its factorization.

13778917 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 74088, while the sum is 43.

The square root of 13778917 is about 3711.9963631448. The cubic root of 13778917 is about 239.7388188808.

The spelling of 13778917 in words is "thirteen million, seven hundred seventy-eight thousand, nine hundred seventeen".