21121222221111 has 8 divisors (see below), whose sum is σ = 28161923493744. Its totient is φ = 14080667881280.

The previous prime is 21121222221109. The next prime is 21121222221137. The reversal of 21121222221111 is 11112222212112.

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 21121222221111 - 2¹ = 21121222221109 is a prime.

It is a super-2 number, since 2×21121222221111² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121222721111) 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, 36397350 + ... + 36973091.

It is an arithmetic number, because the mean of its divisors is an integer number (3520240436718).

Almost surely, 2^{21121222221111} is an apocalyptic number.

21121222221111 is a deficient number, since it is larger than the sum of its proper divisors (7040701272633).

21121222221111 is an equidigital number, since it uses as much as digits as its factorization.

21121222221111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73466401.

The product of its digits is 128, while the sum is 21.

Adding to 21121222221111 its reverse (11112222212112), we get a palindrome (32233444433223).

The spelling of 21121222221111 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twenty-two million, two hundred twenty-one thousand, one hundred eleven".