21243143123 has 2 divisors, whose sum is σ = 21243143124. Its totient is φ = 21243143122.

The previous prime is 21243142997. The next prime is 21243143149. The reversal of 21243143123 is 32134134212.

It is an a-pointer prime, because the next prime (21243143149) can be obtained adding 21243143123 to its sum of digits (26).

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21243143123 - 2⁸ = 21243142867 is a prime.

It is a super-2 number, since 2×21243143123² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21243143092 and 21243143101.

It is not a weakly prime, because it can be changed into another prime (21243143323) 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, 10621571561 + 10621571562.

It is an arithmetic number, because the mean of its divisors is an integer number (10621571562).

Almost surely, 2^21243143123 is an apocalyptic number.

21243143123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243143123 is an equidigital number, since it uses as much as digits as its factorization.

21243143123 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3456, while the sum is 26.

Adding to 21243143123 its reverse (32134134212), we get a palindrome (53377277335).

The spelling of 21243143123 in words is "twenty-one billion, two hundred forty-three million, one hundred forty-three thousand, one hundred twenty-three".