1242123109 has 2 divisors, whose sum is σ = 1242123110. Its totient is φ = 1242123108.

The previous prime is 1242123101. The next prime is 1242123143. The reversal of 1242123109 is 9013212421.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 785232484 + 456890625 = 28022^2 + 21375^2 .

It is a cyclic number.

It is not a de Polignac number, because 1242123109 - 2³ = 1242123101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1242123101) 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, 621061554 + 621061555.

It is an arithmetic number, because the mean of its divisors is an integer number (621061555).

Almost surely, 2^1242123109 is an apocalyptic number.

It is an amenable number.

1242123109 is a deficient number, since it is larger than the sum of its proper divisors (1).

1242123109 is an equidigital number, since it uses as much as digits as its factorization.

1242123109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 1242123109 is about 35243.7669524698. The cubic root of 1242123109 is about 1074.9498758673.

The spelling of 1242123109 in words is "one billion, two hundred forty-two million, one hundred twenty-three thousand, one hundred nine".