| Base | Representation |
|---|---|
| bin | 100100011001101… |
| … | …1011001011011100 |
| 3 | 10011010100120222200 |
| 4 | 1020303123023130 |
| 5 | 10000142041340 |
| 6 | 321111411500 |
| 7 | 42161033130 |
| oct | 11063331334 |
| 9 | 3133316880 |
| 10 | 1221440220 |
| 11 | 577520130 |
| 12 | 2a1083b90 |
| 13 | 1660902c0 |
| 14 | b83113c0 |
| 15 | 72373330 |
| hex | 48cdb2dc |
1221440220 has 288 divisors, whose sum is σ = 4975326720. Its totient is φ = 234247680.
The previous prime is 1221440197. The next prime is 1221440239. The reversal of 1221440220 is 220441221.
1221440220 is a `hidden beast` number, since 1 + 2 + 2 + 1 + 440 + 220 = 666.
It is a super-2 number, since 2×12214402202 = 2983832422067296800, which contains 22 as substring.
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 = 1221440193 and 1221440202.
It is a congruent number.
It is an unprimeable number.
It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 176791 + ... + 183569.
It is an arithmetic number, because the mean of its divisors is an integer number (17275440).
Almost surely, 21221440220 is an apocalyptic number.
1221440220 is a gapful number since it is divisible by the number (10) 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 1221440220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2487663360).
1221440220 is an abundant number, since it is smaller than the sum of its proper divisors (3753886500).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
1221440220 is a wasteful number, since it uses less digits than its factorization.
1221440220 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 6825 (or 6820 counting only the distinct ones).
The product of its (nonzero) digits is 256, while the sum is 18.
The square root of 1221440220 is about 34949.1090015182. The cubic root of 1221440220 is about 1068.9500341698.
Adding to 1221440220 its reverse (220441221), we get a palindrome (1441881441).
The spelling of 1221440220 in words is "one billion, two hundred twenty-one million, four hundred forty thousand, two hundred twenty".
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