221101121981 has 2 divisors, whose sum is σ = 221101121982. Its totient is φ = 221101121980.

The previous prime is 221101121971. The next prime is 221101122017. The reversal of 221101121981 is 189121101122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 139322281081 + 81778840900 = 373259^2 + 285970^2 .

It is a cyclic number.

It is not a de Polignac number, because 221101121981 - 2¹⁴ = 221101105597 is a prime.

It is a super-2 number, since 2×221101121981² (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 (221101121921) 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, 110550560990 + 110550560991.

It is an arithmetic number, because the mean of its divisors is an integer number (110550560991).

Almost surely, 2^221101121981 is an apocalyptic number.

It is an amenable number.

221101121981 is a deficient number, since it is larger than the sum of its proper divisors (1).

221101121981 is an equidigital number, since it uses as much as digits as its factorization.

221101121981 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 221101121981 in words is "two hundred twenty-one billion, one hundred one million, one hundred twenty-one thousand, nine hundred eighty-one".