21112100120981 has 2 divisors, whose sum is σ = 21112100120982. Its totient is φ = 21112100120980.

The previous prime is 21112100120971. The next prime is 21112100121017. The reversal of 21112100120981 is 18902100121112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10947264082225 + 10164836038756 = 3308665^2 + 3188234^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21112100120981 is a prime.

It is a super-2 number, since 2×21112100120981² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21112100120971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556050060490 + 10556050060491.

It is an arithmetic number, because the mean of its divisors is an integer number (10556050060491).

Almost surely, 2^{21112100120981} is an apocalyptic number.

It is an amenable number.

21112100120981 is a deficient number, since it is larger than the sum of its proper divisors (1).

21112100120981 is an equidigital number, since it uses as much as digits as its factorization.

21112100120981 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 29.

The spelling of 21112100120981 in words is "twenty-one trillion, one hundred twelve billion, one hundred million, one hundred twenty thousand, nine hundred eighty-one".