121909 has 2 divisors, whose sum is σ = 121910. Its totient is φ = 121908.

The previous prime is 121889. The next prime is 121921. The reversal of 121909 is 909121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 103684 + 18225 = 322^2 + 135^2 .

It is a cyclic number.

It is not a de Polignac number, because 121909 - 2¹³ = 113717 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 121909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60954 + 60955.

It is an arithmetic number, because the mean of its divisors is an integer number (60955).

2¹²¹⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

121909 is a deficient number, since it is larger than the sum of its proper divisors (1).

121909 is an equidigital number, since it uses as much as digits as its factorization.

121909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 162, while the sum is 22.

The square root of 121909 is about 349.1546935099. The cubic root of 121909 is about 49.5844221371.

The spelling of 121909 in words is "one hundred twenty-one thousand, nine hundred nine".