21212212212220 has 24 divisors (see below), whose sum is σ = 44607600676800. Its totient is φ = 8473083926592.

The previous prime is 21212212212211. The next prime is 21212212212239. The reversal of 21212212212220 is 2221221221212.

It is a junction number, because it is equal to n+sod(n) for n = 21212212212191 and 21212212212200.

It is a congruent number.

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, 737545155 + ... + 737573914.

It is an arithmetic number, because the mean of its divisors is an integer number (1858650028200).

Almost surely, 2^{21212212212220} is an apocalyptic number.

21212212212220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212212212220 is an abundant number, since it is smaller than the sum of its proper divisors (23395388464580).

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

21212212212220 is a wasteful number, since it uses less digits than its factorization.

21212212212220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1475119797 (or 1475119795 counting only the distinct ones).

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

Adding to 21212212212220 its reverse (2221221221212), we get a palindrome (23433433433432).

The spelling of 21212212212220 in words is "twenty-one trillion, two hundred twelve billion, two hundred twelve million, two hundred twelve thousand, two hundred twenty".