13778309 has 2 divisors, whose sum is σ = 13778310. Its totient is φ = 13778308.

The previous prime is 13778267. The next prime is 13778327. The reversal of 13778309 is 90387731.

It is a happy number.

13778309 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., 12285025 + 1493284 = 3505^2 + 1222^2 .

It is a cyclic number.

It is not a de Polignac number, because 13778309 - 2⁸ = 13778053 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13778339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6889154 + 6889155.

It is an arithmetic number, because the mean of its divisors is an integer number (6889155).

Almost surely, 2^13778309 is an apocalyptic number.

It is an amenable number.

13778309 is a deficient number, since it is larger than the sum of its proper divisors (1).

13778309 is an equidigital number, since it uses as much as digits as its factorization.

13778309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31752, while the sum is 38.

The square root of 13778309 is about 3711.9144656094. The cubic root of 13778309 is about 239.7352926398.

The spelling of 13778309 in words is "thirteen million, seven hundred seventy-eight thousand, three hundred nine".