21211220011021 has 2 divisors, whose sum is σ = 21211220011022. Its totient is φ = 21211220011020.

The previous prime is 21211220010817. The next prime is 21211220011057. The reversal of 21211220011021 is 12011002211212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20487165375625 + 724054635396 = 4526275^2 + 850914^2 .

It is a cyclic number.

It is not a de Polignac number, because 21211220011021 - 2¹¹ = 21211220008973 is a prime.

It is a super-2 number, since 2×21211220011021² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21211220010986 and 21211220011004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21211220011061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605610005510 + 10605610005511.

It is an arithmetic number, because the mean of its divisors is an integer number (10605610005511).

Almost surely, 2^{21211220011021} is an apocalyptic number.

It is an amenable number.

21211220011021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21211220011021 is an equidigital number, since it uses as much as digits as its factorization.

21211220011021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21211220011021 its reverse (12011002211212), we get a palindrome (33222222222233).

The spelling of 21211220011021 in words is "twenty-one trillion, two hundred eleven billion, two hundred twenty million, eleven thousand, twenty-one".