1242105421 has 2 divisors, whose sum is σ = 1242105422. Its totient is φ = 1242105420.

The previous prime is 1242105407. The next prime is 1242105433. The reversal of 1242105421 is 1245012421.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1083068100 + 159037321 = 32910^2 + 12611^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1242105421 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1242105392 and 1242105401.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1242105121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 621052710 + 621052711.

It is an arithmetic number, because the mean of its divisors is an integer number (621052711).

Almost surely, 2^1242105421 is an apocalyptic number.

It is an amenable number.

1242105421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1242105421 is an equidigital number, since it uses as much as digits as its factorization.

1242105421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 640, while the sum is 22.

The square root of 1242105421 is about 35243.5160135875. The cubic root of 1242105421 is about 1074.9447733662.

Adding to 1242105421 its reverse (1245012421), we get a palindrome (2487117842).

The spelling of 1242105421 in words is "one billion, two hundred forty-two million, one hundred five thousand, four hundred twenty-one".