13778509 has 8 divisors (see below), whose sum is σ = 14295960. Its totient is φ = 13263936.

The previous prime is 13778507. The next prime is 13778543. The reversal of 13778509 is 90587731.

13778509 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 162409 + 13616100 = 403^2 + 3690^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 13778509 - 2¹ = 13778507 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13778507) 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 in 7 ways as a sum of consecutive naturals, for example, 15727 + ... + 16579.

It is an arithmetic number, because the mean of its divisors is an integer number (1786995).

Almost surely, 2^13778509 is an apocalyptic number.

It is an amenable number.

13778509 is a deficient number, since it is larger than the sum of its proper divisors (517451).

13778509 is an equidigital number, since it uses as much as digits as its factorization.

13778509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1439.

The product of its (nonzero) digits is 52920, while the sum is 40.

The square root of 13778509 is about 3711.9414057875. The cubic root of 13778509 is about 239.7364525989.

The spelling of 13778509 in words is "thirteen million, seven hundred seventy-eight thousand, five hundred nine".