21220120222020 has 144 divisors (see below), whose sum is σ = 64747854243072. Its totient is φ = 5625376024320.

The previous prime is 21220120221977. The next prime is 21220120222027. The reversal of 21220120222020 is 2022202102212.

21220120222020 is a `hidden beast` number, since 2 + 1 + 220 + 1 + 202 + 220 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21220120221984 and 21220120222002.

It is not an unprimeable number, because it can be changed into a prime (21220120222027) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 20372409 + ... + 21388671.

It is an arithmetic number, because the mean of its divisors is an integer number (449637876688).

Almost surely, 2^{21220120222020} is an apocalyptic number.

21220120222020 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 21220120222020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32373927121536).

21220120222020 is an abundant number, since it is smaller than the sum of its proper divisors (43527734021052).

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

21220120222020 is a wasteful number, since it uses less digits than its factorization.

21220120222020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1016962 (or 1016957 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

Adding to 21220120222020 its reverse (2022202102212), we get a palindrome (23242322324232).

The spelling of 21220120222020 in words is "twenty-one trillion, two hundred twenty billion, one hundred twenty million, two hundred twenty-two thousand, twenty".