21211211101081 has 2 divisors, whose sum is σ = 21211211101082. Its totient is φ = 21211211101080.

The previous prime is 21211211101051. The next prime is 21211211101181. The reversal of 21211211101081 is 18010111211212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13057382250000 + 8153828851081 = 3613500^2 + 2855491^2 .

It is a cyclic number.

It is not a de Polignac number, because 21211211101081 - 2⁷ = 21211211100953 is a prime.

It is a super-2 number, since 2×21211211101081² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21211211101001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605605550540 + 10605605550541.

It is an arithmetic number, because the mean of its divisors is an integer number (10605605550541).

Almost surely, 2^{21211211101081} is an apocalyptic number.

It is an amenable number.

21211211101081 is a deficient number, since it is larger than the sum of its proper divisors (1).

21211211101081 is an equidigital number, since it uses as much as digits as its factorization.

21211211101081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 22.

Adding to 21211211101081 its reverse (18010111211212), we get a palindrome (39221322312293).

The spelling of 21211211101081 in words is "twenty-one trillion, two hundred eleven billion, two hundred eleven million, one hundred one thousand, eighty-one".