21012211121123 has 2 divisors, whose sum is σ = 21012211121124. Its totient is φ = 21012211121122.

The previous prime is 21012211121089. The next prime is 21012211121129. The reversal of 21012211121123 is 32112111221012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21012211121123 - 2⁸ = 21012211120867 is a prime.

It is a super-2 number, since 2×21012211121123² (a number of 27 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 21012211121095 and 21012211121104.

It is not a weakly prime, because it can be changed into another prime (21012211121129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506105560561 + 10506105560562.

It is an arithmetic number, because the mean of its divisors is an integer number (10506105560562).

Almost surely, 2^{21012211121123} is an apocalyptic number.

21012211121123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012211121123 is an equidigital number, since it uses as much as digits as its factorization.

21012211121123 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96, while the sum is 20.

Adding to 21012211121123 its reverse (32112111221012), we get a palindrome (53124322342135).

The spelling of 21012211121123 in words is "twenty-one trillion, twelve billion, two hundred eleven million, one hundred twenty-one thousand, one hundred twenty-three".