20211100000081 has 2 divisors, whose sum is σ = 20211100000082. Its totient is φ = 20211100000080.

The previous prime is 20211100000057. The next prime is 20211100000121. The reversal of 20211100000081 is 18000000111202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20030637313600 + 180462686481 = 4475560^2 + 424809^2 .

It is a cyclic number.

It is not a de Polignac number, because 20211100000081 - 2¹⁹ = 20211099475793 is a prime.

It is a super-2 number, since 2×20211100000081² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20211100000031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10105550000040 + 10105550000041.

It is an arithmetic number, because the mean of its divisors is an integer number (10105550000041).

Almost surely, 2^{20211100000081} is an apocalyptic number.

It is an amenable number.

20211100000081 is a deficient number, since it is larger than the sum of its proper divisors (1).

20211100000081 is an equidigital number, since it uses as much as digits as its factorization.

20211100000081 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 20211100000081 its reverse (18000000111202), we get a palindrome (38211100111283).

The spelling of 20211100000081 in words is "twenty trillion, two hundred eleven billion, one hundred million, eighty-one", and thus it is an aban number.