21102121123 has 2 divisors, whose sum is σ = 21102121124. Its totient is φ = 21102121122.

The previous prime is 21102121093. The next prime is 21102121133. The reversal of 21102121123 is 32112120112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21102121123 - 2⁵ = 21102121091 is a prime.

It is a super-2 number, since 2×21102121123² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21102121097 and 21102121106.

It is not a weakly prime, because it can be changed into another prime (21102121133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551060561 + 10551060562.

It is an arithmetic number, because the mean of its divisors is an integer number (10551060562).

Almost surely, 2^21102121123 is an apocalyptic number.

21102121123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102121123 is an equidigital number, since it uses as much as digits as its factorization.

21102121123 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 21102121123 its reverse (32112120112), we get a palindrome (53214241235).

The spelling of 21102121123 in words is "twenty-one billion, one hundred two million, one hundred twenty-one thousand, one hundred twenty-three".