21221210221111 has 8 divisors (see below), whose sum is σ = 21303474347520. Its totient is φ = 21139100873592.

The previous prime is 21221210221073. The next prime is 21221210221157. The reversal of 21221210221111 is 11112201212212.

It is a happy number.

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 21221210221111 - 2²¹ = 21221208123959 is a prime.

It is a super-4 number, since 4×21221210221111⁴ (a number of 54 digits) contains 4444 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221210221181) 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, 38419975 + ... + 38968408.

It is an arithmetic number, because the mean of its divisors is an integer number (2662934293440).

Almost surely, 2^{21221210221111} is an apocalyptic number.

21221210221111 is a deficient number, since it is larger than the sum of its proper divisors (82264126409).

21221210221111 is an equidigital number, since it uses as much as digits as its factorization.

21221210221111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77389445.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21221210221111 its reverse (11112201212212), we get a palindrome (32333411433323).

The spelling of 21221210221111 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred ten million, two hundred twenty-one thousand, one hundred eleven".