21121221010211 has 6 divisors (see below), whose sum is σ = 24569583624180. Its totient is φ = 18103903722996.

The previous prime is 21121221010207. The next prime is 21121221010223. The reversal of 21121221010211 is 11201012212112.

It is not a de Polignac number, because 21121221010211 - 2² = 21121221010207 is a prime.

It is a super-2 number, since 2×21121221010211² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21121221010211.

It is not an unprimeable number, because it can be changed into a prime (21121221010111) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 215522663321 + ... + 215522663418.

It is an arithmetic number, because the mean of its divisors is an integer number (4094930604030).

Almost surely, 2^{21121221010211} is an apocalyptic number.

21121221010211 is a deficient number, since it is larger than the sum of its proper divisors (3448362613969).

21121221010211 is an equidigital number, since it uses as much as digits as its factorization.

21121221010211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431045326753 (or 431045326746 counting only the distinct ones).

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

Adding to 21121221010211 its reverse (11201012212112), we get a palindrome (32322233222323).

The spelling of 21121221010211 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twenty-one million, ten thousand, two hundred eleven".