21110112021221 has 8 divisors (see below), whose sum is σ = 21135364587480. Its totient is φ = 21084860901888.

The previous prime is 21110112021133. The next prime is 21110112021293. The reversal of 21110112021221 is 12212021101112.

It can be written as a sum of positive squares in 4 ways, for example, as 12475829308996 + 8634282712225 = 3532114^2 + 2938415^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21110112021221 - 2³⁰ = 21109038279397 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21110112021221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110112029221) 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 in 7 ways as a sum of consecutive naturals, for example, 30396365 + ... + 31083101.

It is an arithmetic number, because the mean of its divisors is an integer number (2641920573435).

Almost surely, 2^{21110112021221} is an apocalyptic number.

It is an amenable number.

21110112021221 is a deficient number, since it is larger than the sum of its proper divisors (25252566259).

21110112021221 is an equidigital number, since it uses as much as digits as its factorization.

21110112021221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 723463.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21110112021221 its reverse (12212021101112), we get a palindrome (33322133122333).

The spelling of 21110112021221 in words is "twenty-one trillion, one hundred ten billion, one hundred twelve million, twenty-one thousand, two hundred twenty-one".