212111219981 has 2 divisors, whose sum is σ = 212111219982. Its totient is φ = 212111219980.

The previous prime is 212111219977. The next prime is 212111220019. The reversal of 212111219981 is 189912111212.

It is an a-pointer prime, because the next prime (212111220019) can be obtained adding 212111219981 to its sum of digits (38).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 205036896100 + 7074323881 = 452810^2 + 84109^2 .

It is a cyclic number.

It is not a de Polignac number, because 212111219981 - 2² = 212111219977 is a prime.

It is a super-2 number, since 2×212111219981² (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 (212131219981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106055609990 + 106055609991.

It is an arithmetic number, because the mean of its divisors is an integer number (106055609991).

Almost surely, 2^212111219981 is an apocalyptic number.

It is an amenable number.

212111219981 is a deficient number, since it is larger than the sum of its proper divisors (1).

212111219981 is an equidigital number, since it uses as much as digits as its factorization.

212111219981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 38.

The spelling of 212111219981 in words is "two hundred twelve billion, one hundred eleven million, two hundred nineteen thousand, nine hundred eighty-one".