121609 has 2 divisors, whose sum is σ = 121610. Its totient is φ = 121608.

The previous prime is 121607. The next prime is 121621. The reversal of 121609 is 906121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64009 + 57600 = 253^2 + 240^2 .

It is an emirp because it is prime and its reverse (906121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 121609 - 2¹ = 121607 is a prime.

Together with 121607, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (121607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60804 + 60805.

It is an arithmetic number, because the mean of its divisors is an integer number (60805).

2¹²¹⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

121609 is a deficient number, since it is larger than the sum of its proper divisors (1).

121609 is an equidigital number, since it uses as much as digits as its factorization.

121609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108, while the sum is 19.

The square root of 121609 is about 348.7248198795. The cubic root of 121609 is about 49.5437154205.

The spelling of 121609 in words is "one hundred twenty-one thousand, six hundred nine".