21121021123 has 2 divisors, whose sum is σ = 21121021124. Its totient is φ = 21121021122.

The previous prime is 21121021111. The next prime is 21121021157. The reversal of 21121021123 is 32112012112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21121021123 - 2²¹ = 21118923971 is a prime.

It is a super-2 number, since 2×21121021123² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121021097 and 21121021106.

It is not a weakly prime, because it can be changed into another prime (21121021183) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560510561 + 10560510562.

It is an arithmetic number, because the mean of its divisors is an integer number (10560510562).

Almost surely, 2^21121021123 is an apocalyptic number.

21121021123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121021123 is an equidigital number, since it uses as much as digits as its factorization.

21121021123 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 21121021123 its reverse (32112012112), we get a palindrome (53233033235).

The spelling of 21121021123 in words is "twenty-one billion, one hundred twenty-one million, twenty-one thousand, one hundred twenty-three".