212221219981 has 2 divisors, whose sum is σ = 212221219982. Its totient is φ = 212221219980.

The previous prime is 212221219963. The next prime is 212221220021. The reversal of 212221219981 is 189912122212.

It is an a-pointer prime, because the next prime (212221220021) can be obtained adding 212221219981 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 172914588900 + 39306631081 = 415830^2 + 198259^2 .

It is a cyclic number.

It is not a de Polignac number, because 212221219981 - 2¹¹ = 212221217933 is a prime.

It is a super-2 number, since 2×212221219981² (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 (212221219961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106110609990 + 106110609991.

It is an arithmetic number, because the mean of its divisors is an integer number (106110609991).

Almost surely, 2^212221219981 is an apocalyptic number.

It is an amenable number.

212221219981 is a deficient number, since it is larger than the sum of its proper divisors (1).

212221219981 is an equidigital number, since it uses as much as digits as its factorization.

212221219981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20736, while the sum is 40.

The spelling of 212221219981 in words is "two hundred twelve billion, two hundred twenty-one million, two hundred nineteen thousand, nine hundred eighty-one".