21123223221161 has 2 divisors, whose sum is σ = 21123223221162. Its totient is φ = 21123223221160.

The previous prime is 21123223221019. The next prime is 21123223221169. The reversal of 21123223221161 is 16112232232112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13825985425561 + 7297237795600 = 3718331^2 + 2701340^2 .

It is a cyclic number.

It is not a de Polignac number, because 21123223221161 - 2³⁰ = 21122149479337 is a prime.

It is not a weakly prime, because it can be changed into another prime (21123223221169) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561611610580 + 10561611610581.

It is an arithmetic number, because the mean of its divisors is an integer number (10561611610581).

Almost surely, 2^{21123223221161} is an apocalyptic number.

It is an amenable number.

21123223221161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21123223221161 is an equidigital number, since it uses as much as digits as its factorization.

21123223221161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3456, while the sum is 29.

Adding to 21123223221161 its reverse (16112232232112), we get a palindrome (37235455453273).

The spelling of 21123223221161 in words is "twenty-one trillion, one hundred twenty-three billion, two hundred twenty-three million, two hundred twenty-one thousand, one hundred sixty-one".