| Base | Representation |
|---|---|
| bin | 100101110110011111… |
| … | …0001000000000000000 |
| 3 | 21202210220021221020000 |
| 4 | 1023230332020000000 |
| 5 | 2312432442320000 |
| 6 | 101201502120000 |
| 7 | 5605215056100 |
| oct | 1135476100000 |
| 9 | 252726257200 |
| 10 | 81285120000 |
| 11 | 31522370827 |
| 12 | 13906280000 |
| 13 | 788545cc56 |
| 14 | 3d11705200 |
| 15 | 21ab220000 |
| hex | 12ecf88000 |
81285120000 has 1200 divisors, whose sum is σ = 353008012995. Its totient is φ = 18579456000.
The previous prime is 81285119987. The next prime is 81285120001. The reversal of 81285120000 is 2158218.
It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.
It can be written as a sum of positive squares in 3 ways, for example, as 18793119744 + 62492000256 = 137088^2 + 249984^2 .
It is a tau number, because it is divible by the number of its divisors (1200).
It is an ABA number since it can be written as A⋅BA, here for A=2, B=201600.
It is a Harshad number since it is a multiple of its sum of digits (27).
It is not an unprimeable number, because it can be changed into a prime (81285120001) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (13) of ones.
It is a polite number, since it can be written in 74 ways as a sum of consecutive naturals, for example, 11612159997 + ... + 11612160003.
Almost surely, 281285120000 is an apocalyptic number.
81285120000 is a gapful number since it is divisible by the number (80) 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 81285120000
81285120000 is an abundant number, since it is smaller than the sum of its proper divisors (271722892995).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
81285120000 is an frugal number, since it uses more digits than its factorization.
81285120000 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 76 (or 17 counting only the distinct ones).
The product of its (nonzero) digits is 1280, while the sum is 27.
Adding to 81285120000 its reverse (2158218), we get a palindrome (81287278218).
The spelling of 81285120000 in words is "eighty-one billion, two hundred eighty-five million, one hundred twenty thousand".
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