21211021221222 has 64 divisors (see below), whose sum is σ = 49323097935360. Its totient is φ = 5955275602944.

The previous prime is 21211021221119. The next prime is 21211021221283. The reversal of 21211021221222 is 22212212011212.

It is a super-3 number, since 3×21211021221222³ (a number of 41 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4774908 + ... + 8076000.

It is an arithmetic number, because the mean of its divisors is an integer number (770673405240).

Almost surely, 2^{21211021221222} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21211021221222, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24661548967680).

21211021221222 is an abundant number, since it is smaller than the sum of its proper divisors (28112076714138).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21211021221222 is a wasteful number, since it uses less digits than its factorization.

21211021221222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3303757.

The product of its (nonzero) digits is 256, while the sum is 21.

Adding to 21211021221222 its reverse (22212212011212), we get a palindrome (43423233232434).

The spelling of 21211021221222 in words is "twenty-one trillion, two hundred eleven billion, twenty-one million, two hundred twenty-one thousand, two hundred twenty-two".