21161005500121 has 2 divisors, whose sum is σ = 21161005500122. Its totient is φ = 21161005500120.

The previous prime is 21161005500091. The next prime is 21161005500149. The reversal of 21161005500121 is 12100550016112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21142854674496 + 18150825625 = 4598136^2 + 134725^2 .

It is a cyclic number.

It is not a de Polignac number, because 21161005500121 - 2¹⁹ = 21161004975833 is a prime.

It is not a weakly prime, because it can be changed into another prime (21161005501121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10580502750060 + 10580502750061.

It is an arithmetic number, because the mean of its divisors is an integer number (10580502750061).

Almost surely, 2^{21161005500121} is an apocalyptic number.

It is an amenable number.

21161005500121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21161005500121 is an equidigital number, since it uses as much as digits as its factorization.

21161005500121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 600, while the sum is 25.

Adding to 21161005500121 its reverse (12100550016112), we get a palindrome (33261555516233).

The spelling of 21161005500121 in words is "twenty-one trillion, one hundred sixty-one billion, five million, five hundred thousand, one hundred twenty-one".