123121121309 has 2 divisors, whose sum is σ = 123121121310. Its totient is φ = 123121121308.

The previous prime is 123121121297. The next prime is 123121121311. The reversal of 123121121309 is 903121121321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 98311721209 + 24809400100 = 313547^2 + 157510^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-123121121309 is a prime.

Together with 123121121311, 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 (123121121329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61560560654 + 61560560655.

It is an arithmetic number, because the mean of its divisors is an integer number (61560560655).

Almost surely, 2^123121121309 is an apocalyptic number.

It is an amenable number.

123121121309 is a deficient number, since it is larger than the sum of its proper divisors (1).

123121121309 is an equidigital number, since it uses as much as digits as its factorization.

123121121309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 26.

The spelling of 123121121309 in words is "one hundred twenty-three billion, one hundred twenty-one million, one hundred twenty-one thousand, three hundred nine".