10212121981 has 2 divisors, whose sum is σ = 10212121982. Its totient is φ = 10212121980.

The previous prime is 10212121961. The next prime is 10212121999. The reversal of 10212121981 is 18912121201.

10212121981 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., 6936391225 + 3275730756 = 83285^2 + 57234^2 .

It is an emirp because it is prime and its reverse (18912121201) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 10212121981 - 2¹³ = 10212113789 is a prime.

It is a super-2 number, since 2×10212121981² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (10212121961) 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, 5106060990 + 5106060991.

It is an arithmetic number, because the mean of its divisors is an integer number (5106060991).

Almost surely, 2^10212121981 is an apocalyptic number.

It is an amenable number.

10212121981 is a deficient number, since it is larger than the sum of its proper divisors (1).

10212121981 is an equidigital number, since it uses as much as digits as its factorization.

10212121981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 28.

The spelling of 10212121981 in words is "ten billion, two hundred twelve million, one hundred twenty-one thousand, nine hundred eighty-one".