21210443123 has 2 divisors, whose sum is σ = 21210443124. Its totient is φ = 21210443122.

The previous prime is 21210443069. The next prime is 21210443129. The reversal of 21210443123 is 32134401212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21210443123 - 2⁸ = 21210442867 is a prime.

It is not a weakly prime, because it can be changed into another prime (21210443129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605221561 + 10605221562.

It is an arithmetic number, because the mean of its divisors is an integer number (10605221562).

Almost surely, 2^21210443123 is an apocalyptic number.

21210443123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210443123 is an equidigital number, since it uses as much as digits as its factorization.

21210443123 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 23.

Adding to 21210443123 its reverse (32134401212), we get a palindrome (53344844335).

The spelling of 21210443123 in words is "twenty-one billion, two hundred ten million, four hundred forty-three thousand, one hundred twenty-three".