21122012123 has 2 divisors, whose sum is σ = 21122012124. Its totient is φ = 21122012122.

The previous prime is 21122012053. The next prime is 21122012129. The reversal of 21122012123 is 32121022112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21122012123 - 2³² = 16827044827 is a prime.

It is a super-2 number, since 2×21122012123² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21122012129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561006061 + 10561006062.

It is an arithmetic number, because the mean of its divisors is an integer number (10561006062).

Almost surely, 2^21122012123 is an apocalyptic number.

21122012123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21122012123 is an equidigital number, since it uses as much as digits as its factorization.

21122012123 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21122012123 its reverse (32121022112), we get a palindrome (53243034235).

The spelling of 21122012123 in words is "twenty-one billion, one hundred twenty-two million, twelve thousand, one hundred twenty-three".