13778609 has 4 divisors (see below), whose sum is σ = 14838516. Its totient is φ = 12718704.

The previous prime is 13778603. The next prime is 13778623. The reversal of 13778609 is 90687731.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4494400 + 9284209 = 2120^2 + 3047^2 .

It is a cyclic number.

It is not a de Polignac number, because 13778609 - 2⁴ = 13778593 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (13778603) 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 3 ways as a sum of consecutive naturals, for example, 529934 + ... + 529959.

It is an arithmetic number, because the mean of its divisors is an integer number (3709629).

Almost surely, 2^13778609 is an apocalyptic number.

It is an amenable number.

13778609 is a deficient number, since it is larger than the sum of its proper divisors (1059907).

13778609 is a wasteful number, since it uses less digits than its factorization.

13778609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1059906.

The product of its (nonzero) digits is 63504, while the sum is 41.

The square root of 13778609 is about 3711.9548758033. The cubic root of 13778609 is about 239.7370325743.

The spelling of 13778609 in words is "thirteen million, seven hundred seventy-eight thousand, six hundred nine".