| Base | Representation |
|---|---|
| bin | 10011101011000011… |
| … | …000010011001110100 |
| 3 | 2000112010020101120000 |
| 4 | 103223003002121310 |
| 5 | 321230031424340 |
| 6 | 13412013511300 |
| 7 | 1345312116504 |
| oct | 235303023164 |
| 9 | 60463211500 |
| 10 | 21123311220 |
| 11 | 8a5a616400 |
| 12 | 41161a2530 |
| 13 | 1cb832ac2b |
| 14 | 1045571a04 |
| 15 | 8396a8d30 |
| hex | 4eb0c2674 |
21123311220 has 180 divisors, whose sum is σ = 72836982372. Its totient is φ = 5120755200.
The previous prime is 21123311219. The next prime is 21123311227. The reversal of 21123311220 is 2211332112.
21123311220 is a `hidden beast` number, since 2 + 112 + 331 + 1 + 220 = 666.
It can be written as a sum of positive squares in 2 ways, for example, as 7798302864 + 13325008356 = 88308^2 + 115434^2 .
It is a tau number, because it is divible by the number of its divisors (180).
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 = 21123311193 and 21123311202.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (21123311227) by changing a digit.
It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 142140 + ... + 249900.
Almost surely, 221123311220 is an apocalyptic number.
21123311220 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 21123311220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36418491186).
21123311220 is an abundant number, since it is smaller than the sum of its proper divisors (51713671152).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
21123311220 is a wasteful number, since it uses less digits than its factorization.
21123311220 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 107804 (or 107782 counting only the distinct ones).
The product of its (nonzero) digits is 144, while the sum is 18.
Adding to 21123311220 its reverse (2211332112), we get a palindrome (23334643332).
The spelling of 21123311220 in words is "twenty-one billion, one hundred twenty-three million, three hundred eleven thousand, two hundred twenty".
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