21121001101121 has 4 divisors (see below), whose sum is σ = 21338743380612. Its totient is φ = 20903258821632.

The previous prime is 21121001101099. The next prime is 21121001101127. The reversal of 21121001101121 is 12110110012112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14589833072896 + 6531168028225 = 3819664^2 + 2555615^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121001101121 - 2¹⁰ = 21121001100097 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21121001101096 and 21121001101105.

It is not an unprimeable number, because it can be changed into a prime (21121001101127) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 108871139600 + ... + 108871139793.

It is an arithmetic number, because the mean of its divisors is an integer number (5334685845153).

Almost surely, 2^{21121001101121} is an apocalyptic number.

It is an amenable number.

21121001101121 is a deficient number, since it is larger than the sum of its proper divisors (217742279491).

21121001101121 is an equidigital number, since it uses as much as digits as its factorization.

21121001101121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217742279490.

The product of its (nonzero) digits is 8, while the sum is 14.

Adding to 21121001101121 its reverse (12110110012112), we get a palindrome (33231111113233).

The spelling of 21121001101121 in words is "twenty-one trillion, one hundred twenty-one billion, one million, one hundred one thousand, one hundred twenty-one".