211001209981 has 2 divisors, whose sum is σ = 211001209982. Its totient is φ = 211001209980.

The previous prime is 211001209963. The next prime is 211001209987. The reversal of 211001209981 is 189902100112.

211001209981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 210925258756 + 75951225 = 459266^2 + 8715^2 .

It is a cyclic number.

It is not a de Polignac number, because 211001209981 - 2⁹ = 211001209469 is a prime.

It is a super-2 number, since 2×211001209981² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211001209987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105500604990 + 105500604991.

It is an arithmetic number, because the mean of its divisors is an integer number (105500604991).

Almost surely, 2^211001209981 is an apocalyptic number.

It is an amenable number.

211001209981 is a deficient number, since it is larger than the sum of its proper divisors (1).

211001209981 is an equidigital number, since it uses as much as digits as its factorization.

211001209981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 34.

The spelling of 211001209981 in words is "two hundred eleven billion, one million, two hundred nine thousand, nine hundred eighty-one".