21011001121001 has 2 divisors, whose sum is σ = 21011001121002. Its totient is φ = 21011001121000.

The previous prime is 21011001120911. The next prime is 21011001121003. The reversal of 21011001121001 is 10012110011012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13615184895376 + 7395816225625 = 3689876^2 + 2719525^2 .

It is a cyclic number.

It is not a de Polignac number, because 21011001121001 - 2²⁶ = 21010934012137 is a prime.

Together with 21011001121003, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21011001121003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505500560500 + 10505500560501.

It is an arithmetic number, because the mean of its divisors is an integer number (10505500560501).

Almost surely, 2^{21011001121001} is an apocalyptic number.

It is an amenable number.

21011001121001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011001121001 is an equidigital number, since it uses as much as digits as its factorization.

21011001121001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21011001121001 its reverse (10012110011012), we get a palindrome (31023111132013).

It can be divided in two parts, 210110011 and 21001, that added together give a palindrome (210131012).

The spelling of 21011001121001 in words is "twenty-one trillion, eleven billion, one million, one hundred twenty-one thousand, one".