21230421161 has 2 divisors, whose sum is σ = 21230421162. Its totient is φ = 21230421160.

The previous prime is 21230421133. The next prime is 21230421167. The reversal of 21230421161 is 16112403212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15643755625 + 5586665536 = 125075^2 + 74744^2 .

It is a cyclic number.

It is not a de Polignac number, because 21230421161 - 2⁶ = 21230421097 is a prime.

It is not a weakly prime, because it can be changed into another prime (21230421167) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615210580 + 10615210581.

It is an arithmetic number, because the mean of its divisors is an integer number (10615210581).

Almost surely, 2^21230421161 is an apocalyptic number.

It is an amenable number.

21230421161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21230421161 is an equidigital number, since it uses as much as digits as its factorization.

21230421161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 23.

Adding to 21230421161 its reverse (16112403212), we get a palindrome (37342824373).

The spelling of 21230421161 in words is "twenty-one billion, two hundred thirty million, four hundred twenty-one thousand, one hundred sixty-one".