| Base | Representation |
|---|---|
| bin | 1001101001010110110101… |
| … | …10110000101111110111100 |
| 3 | 2210002212110002111002021000 |
| 4 | 10310223122312011332330 |
| 5 | 10240020111322333040 |
| 6 | 113040432010210300 |
| 7 | 4316350406030625 |
| oct | 464533266057674 |
| 9 | 83085402432230 |
| 10 | 21212220121020 |
| 11 | 68390632909a5 |
| 12 | 24670a1723990 |
| 13 | bab3c4513a86 |
| 14 | 534969702a4c |
| 15 | 26bba27c3130 |
| hex | 134adad85fbc |
21212220121020 has 192 divisors, whose sum is σ = 67297058357760. Its totient is φ = 5545954842624.
The previous prime is 21212220121003. The next prime is 21212220121021. The reversal of 21212220121020 is 2012102221212.
It is a happy number.
21212220121020 is a `hidden beast` number, since 2 + 1 + 212 + 220 + 1 + 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 = 21212220120984 and 21212220121002.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (21212220121021) by changing a digit.
It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3712287 + ... + 7497033.
It is an arithmetic number, because the mean of its divisors is an integer number (350505512280).
Almost surely, 221212220121020 is an apocalyptic number.
21212220121020 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 21212220121020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33648529178880).
21212220121020 is an abundant number, since it is smaller than the sum of its proper divisors (46084838236740).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
21212220121020 is a wasteful number, since it uses less digits than its factorization.
21212220121020 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 3784969 (or 3784961 counting only the distinct ones).
The product of its (nonzero) digits is 128, while the sum is 18.
Adding to 21212220121020 its reverse (2012102221212), we get a palindrome (23224322342232).
The spelling of 21212220121020 in words is "twenty-one trillion, two hundred twelve billion, two hundred twenty million, one hundred twenty-one thousand, twenty".
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