21212211222220 has 96 divisors (see below), whose sum is σ = 47745887809536. Its totient is φ = 7896448243200.

The previous prime is 21212211222217. The next prime is 21212211222271. The reversal of 21212211222220 is 2222211221212.

It is a super-2 number, since 2×21212211222220² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21212211222191 and 21212211222200.

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, 5389305 + ... + 8453935.

It is an arithmetic number, because the mean of its divisors is an integer number (497352998016).

Almost surely, 2^{21212211222220} is an apocalyptic number.

21212211222220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21212211222220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23872943904768).

21212211222220 is an abundant number, since it is smaller than the sum of its proper divisors (26533676587316).

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

21212211222220 is a wasteful number, since it uses less digits than its factorization.

21212211222220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3065071 (or 3065069 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 22.

Adding to 21212211222220 its reverse (2222211221212), we get a palindrome (23434422443432).

The spelling of 21212211222220 in words is "twenty-one trillion, two hundred twelve billion, two hundred eleven million, two hundred twenty-two thousand, two hundred twenty".