21212110222220 has 24 divisors (see below), whose sum is σ = 44573858738304. Its totient is φ = 8479429370496.

The previous prime is 21212110222217. The next prime is 21212110222267. The reversal of 21212110222220 is 2222201121212.

It is a super-3 number, since 3×21212110222220³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21212110222192 and 21212110222201.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 338387777 + ... + 338450456.

It is an arithmetic number, because the mean of its divisors is an integer number (1857244114096).

Almost surely, 2^{21212110222220} is an apocalyptic number.

21212110222220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212110222220 is an abundant number, since it is smaller than the sum of its proper divisors (23361748516084).

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

21212110222220 is a wasteful number, since it uses less digits than its factorization.

21212110222220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 676839809 (or 676839807 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 21212110222220 its reverse (2222201121212), we get a palindrome (23434311343432).

The spelling of 21212110222220 in words is "twenty-one trillion, two hundred twelve billion, one hundred ten million, two hundred twenty-two thousand, two hundred twenty".