21220121221020 has 288 divisors, whose sum is σ = 67108204800000. Its totient is φ = 5423379287040.

The previous prime is 21220121220943. The next prime is 21220121221027. The reversal of 21220121221020 is 2012212102212.

It is a happy number.

21220121221020 is a `hidden beast` number, since 2 + 1 + 220 + 1 + 212 + 210 + 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 = 21220121220984 and 21220121221002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220121221027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 115929531 + ... + 116112429.

It is an arithmetic number, because the mean of its divisors is an integer number (233014600000).

Almost surely, 2^{21220121221020} is an apocalyptic number.

21220121221020 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 21220121221020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33554102400000).

21220121221020 is an abundant number, since it is smaller than the sum of its proper divisors (45888083578980).

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

21220121221020 is a wasteful number, since it uses less digits than its factorization.

21220121221020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 183233 (or 183228 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21220121221020 its reverse (2012212102212), we get a palindrome (23232333323232).

The spelling of 21220121221020 in words is "twenty-one trillion, two hundred twenty billion, one hundred twenty-one million, two hundred twenty-one thousand, twenty".