21121200000221 has 8 divisors (see below), whose sum is σ = 21156738093624. Its totient is φ = 21085663219200.

The previous prime is 21121200000169. The next prime is 21121200000289. The reversal of 21121200000221 is 12200000212112.

It can be written as a sum of positive squares in 4 ways, for example, as 773784122500 + 20347415877721 = 879650^2 + 4510811^2 .

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 21121200000221 - 2³⁴ = 21104020131037 is a prime.

It is a super-2 number, since 2×21121200000221² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121200000196 and 21121200000205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121200000421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35098751 + ... + 35695443.

It is an arithmetic number, because the mean of its divisors is an integer number (2644592261703).

Almost surely, 2^{21121200000221} is an apocalyptic number.

It is an amenable number.

21121200000221 is a deficient number, since it is larger than the sum of its proper divisors (35538093403).

21121200000221 is an equidigital number, since it uses as much as digits as its factorization.

21121200000221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 656191.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21121200000221 its reverse (12200000212112), we get a palindrome (33321200212333).

The spelling of 21121200000221 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred million, two hundred twenty-one", and thus it is an aban number.