| Base | Representation |
|---|---|
| bin | 10110100110001010… |
| … | …10100010110000100 |
| 3 | 1011022110012222012100 |
| 4 | 23103011110112010 |
| 5 | 144321104234340 |
| 6 | 5323440152100 |
| 7 | 606424346304 |
| oct | 132305242604 |
| 9 | 34273188170 |
| 10 | 12131321220 |
| 11 | 51658a6207 |
| 12 | 2426908630 |
| 13 | 11b44237a5 |
| 14 | 831243604 |
| 15 | 4b0060830 |
| hex | 2d3154584 |
12131321220 has 144 divisors (see below), whose sum is σ = 37303746480. Its totient is φ = 3190775808.
The previous prime is 12131321201. The next prime is 12131321221. The reversal of 12131321220 is 2212313121.
12131321220 is a `hidden beast` number, since 121 + 3 + 1 + 321 + 220 = 666.
It can be written as a sum of positive squares in 8 ways, for example, as 118722816 + 12012598404 = 10896^2 + 109602^2 .
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 = 12131321193 and 12131321202.
It is not an unprimeable number, because it can be changed into a prime (12131321221) 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, 9499222 + ... + 9500498.
It is an arithmetic number, because the mean of its divisors is an integer number (259053795).
Almost surely, 212131321220 is an apocalyptic number.
12131321220 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 12131321220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18651873240).
12131321220 is an abundant number, since it is smaller than the sum of its proper divisors (25172425260).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
12131321220 is a wasteful number, since it uses less digits than its factorization.
12131321220 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 1974 (or 1969 counting only the distinct ones).
The product of its (nonzero) digits is 144, while the sum is 18.
Adding to 12131321220 its reverse (2212313121), we get a palindrome (14343634341).
The spelling of 12131321220 in words is "twelve billion, one hundred thirty-one million, three hundred twenty-one thousand, two hundred twenty".
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