13778861 has 2 divisors, whose sum is σ = 13778862. Its totient is φ = 13778860.

The previous prime is 13778851. The next prime is 13778867. The reversal of 13778861 is 16887731.

13778861 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., 13645636 + 133225 = 3694^2 + 365^2 .

It is a cyclic number.

It is not a de Polignac number, because 13778861 - 2²² = 9584557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13778867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6889430 + 6889431.

It is an arithmetic number, because the mean of its divisors is an integer number (6889431).

Almost surely, 2^13778861 is an apocalyptic number.

It is an amenable number.

13778861 is a deficient number, since it is larger than the sum of its proper divisors (1).

13778861 is an equidigital number, since it uses as much as digits as its factorization.

13778861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 56448, while the sum is 41.

The square root of 13778861 is about 3711.9888200263. The cubic root of 13778861 is about 239.7384940998.

The spelling of 13778861 in words is "thirteen million, seven hundred seventy-eight thousand, eight hundred sixty-one".