123121232009 has 2 divisors, whose sum is σ = 123121232010. Its totient is φ = 123121232008.

The previous prime is 123121231973. The next prime is 123121232029. The reversal of 123121232009 is 900232121321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 117201468409 + 5919763600 = 342347^2 + 76940^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-123121232009 is a prime.

It is not a weakly prime, because it can be changed into another prime (123121232029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61560616004 + 61560616005.

It is an arithmetic number, because the mean of its divisors is an integer number (61560616005).

Almost surely, 2^123121232009 is an apocalyptic number.

It is an amenable number.

123121232009 is a deficient number, since it is larger than the sum of its proper divisors (1).

123121232009 is an equidigital number, since it uses as much as digits as its factorization.

123121232009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 26.

The spelling of 123121232009 in words is "one hundred twenty-three billion, one hundred twenty-one million, two hundred thirty-two thousand, nine".