121789 has 2 divisors, whose sum is σ = 121790. Its totient is φ = 121788.

The previous prime is 121787. The next prime is 121843. The reversal of 121789 is 987121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66564 + 55225 = 258^2 + 235^2 .

It is a cyclic number.

It is not a de Polignac number, because 121789 - 2¹ = 121787 is a prime.

Together with 121787, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121787) 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 as a sum of consecutive naturals, namely, 60894 + 60895.

It is an arithmetic number, because the mean of its divisors is an integer number (60895).

2¹²¹⁷⁸⁹ is an apocalyptic number.

It is an amenable number.

121789 is a deficient number, since it is larger than the sum of its proper divisors (1).

121789 is an equidigital number, since it uses as much as digits as its factorization.

121789 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1008, while the sum is 28.

The square root of 121789 is about 348.9828075995. The cubic root of 121789 is about 49.5681474731.

The spelling of 121789 in words is "one hundred twenty-one thousand, seven hundred eighty-nine".