21130242121 has 2 divisors, whose sum is σ = 21130242122. Its totient is φ = 21130242120.

The previous prime is 21130242113. The next prime is 21130242169. The reversal of 21130242121 is 12124203112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20404694025 + 725548096 = 142845^2 + 26936^2 .

It is a cyclic number.

It is not a de Polignac number, because 21130242121 - 2³ = 21130242113 is a prime.

It is not a weakly prime, because it can be changed into another prime (21130249121) 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, 10565121060 + 10565121061.

It is an arithmetic number, because the mean of its divisors is an integer number (10565121061).

Almost surely, 2^21130242121 is an apocalyptic number.

It is an amenable number.

21130242121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21130242121 is an equidigital number, since it uses as much as digits as its factorization.

21130242121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 21130242121 its reverse (12124203112), we get a palindrome (33254445233).

The spelling of 21130242121 in words is "twenty-one billion, one hundred thirty million, two hundred forty-two thousand, one hundred twenty-one".