21121001101021 has 2 divisors, whose sum is σ = 21121001101022. Its totient is φ = 21121001101020.

The previous prime is 21121001100919. The next prime is 21121001101049. The reversal of 21121001101021 is 12010110012112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21120816956121 + 184144900 = 4595739^2 + 13570^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121001101021 - 2¹¹ = 21121001098973 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21121001100992 and 21121001101010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21121001107021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560500550510 + 10560500550511.

It is an arithmetic number, because the mean of its divisors is an integer number (10560500550511).

Almost surely, 2^{21121001101021} is an apocalyptic number.

It is an amenable number.

21121001101021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121001101021 is an equidigital number, since it uses as much as digits as its factorization.

21121001101021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21121001101021 its reverse (12010110012112), we get a palindrome (33131111113133).

The spelling of 21121001101021 in words is "twenty-one trillion, one hundred twenty-one billion, one million, one hundred one thousand, twenty-one".