13947809 has 2 divisors, whose sum is σ = 13947810. Its totient is φ = 13947808.

The previous prime is 13947793. The next prime is 13947823. The reversal of 13947809 is 90874931.

It is a happy number.

13947809 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., 12250000 + 1697809 = 3500^2 + 1303^2 .

It is a cyclic number.

It is not a de Polignac number, because 13947809 - 2⁴ = 13947793 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (13947839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6973904 + 6973905.

It is an arithmetic number, because the mean of its divisors is an integer number (6973905).

Almost surely, 2^13947809 is an apocalyptic number.

It is an amenable number.

13947809 is a deficient number, since it is larger than the sum of its proper divisors (1).

13947809 is an equidigital number, since it uses as much as digits as its factorization.

13947809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54432, while the sum is 41.

The square root of 13947809 is about 3734.6765589539. The cubic root of 13947809 is about 240.7143588731.

The spelling of 13947809 in words is "thirteen million, nine hundred forty-seven thousand, eight hundred nine".