21021222012220 has 24 divisors (see below), whose sum is σ = 44145403205904. Its totient is φ = 8408329380096.

The previous prime is 21021222012191. The next prime is 21021222012223. The reversal of 21021222012220 is 2221022212012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021222012223) 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, 8879949 + ... + 10995268.

It is an arithmetic number, because the mean of its divisors is an integer number (1839391800246).

Almost surely, 2^{21021222012220} is an apocalyptic number.

21021222012220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021222012220 is an abundant number, since it is smaller than the sum of its proper divisors (23124181193684).

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

21021222012220 is a wasteful number, since it uses less digits than its factorization.

21021222012220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19928109 (or 19928107 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

Adding to 21021222012220 its reverse (2221022212012), we get a palindrome (23242244224232).

The spelling of 21021222012220 in words is "twenty-one trillion, twenty-one billion, two hundred twenty-two million, twelve thousand, two hundred twenty".