21111201221989 has 2 divisors, whose sum is σ = 21111201221990. Its totient is φ = 21111201221988.

The previous prime is 21111201221959. The next prime is 21111201222031. The reversal of 21111201221989 is 98912210211112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20967698902500 + 143502319489 = 4579050^2 + 378817^2 .

It is a cyclic number.

It is not a de Polignac number, because 21111201221989 - 2⁷ = 21111201221861 is a prime.

It is a super-2 number, since 2×21111201221989² (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 (21111201221959) 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, 10555600610994 + 10555600610995.

It is an arithmetic number, because the mean of its divisors is an integer number (10555600610995).

Almost surely, 2^{21111201221989} is an apocalyptic number.

It is an amenable number.

21111201221989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111201221989 is an equidigital number, since it uses as much as digits as its factorization.

21111201221989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 40.

The spelling of 21111201221989 in words is "twenty-one trillion, one hundred eleven billion, two hundred one million, two hundred twenty-one thousand, nine hundred eighty-nine".