| Base | Representation |
|---|---|
| bin | 1001101110110… |
| … | …11110111110000 |
| 3 | 12200121210022200 |
| 4 | 10313123313300 |
| 5 | 131400002234 |
| 6 | 12033503200 |
| 7 | 2010636150 |
| oct | 467336760 |
| 9 | 180553280 |
| 10 | 81640944 |
| 11 | 420a2060 |
| 12 | 23411b00 |
| 13 | 13bb6268 |
| 14 | abb2760 |
| 15 | 7279d99 |
| hex | 4ddbdf0 |
81640944 has 240 divisors, whose sum is σ = 294028800. Its totient is φ = 20528640.
The previous prime is 81640943. The next prime is 81640991. The reversal of 81640944 is 44904618.
It is a happy number.
81640944 is a `hidden beast` number, since 8 + 1 + 640 + 9 + 4 + 4 = 666.
It is a super-2 number, since 2×816409442 = 13330487474422272, which contains 22 as substring.
It is a Harshad number since it is a multiple of its sum of digits (36).
It is a junction number, because it is equal to n+sod(n) for n = 81640899 and 81640908.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (81640943) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (17) of ones.
It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 410157 + ... + 410355.
It is an arithmetic number, because the mean of its divisors is an integer number (1225120).
Almost surely, 281640944 is an apocalyptic number.
81640944 is a gapful number since it is divisible by the number (84) 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 81640944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (147014400).
81640944 is an abundant number, since it is smaller than the sum of its proper divisors (212387856).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
81640944 is a wasteful number, since it uses less digits than its factorization.
81640944 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 268 (or 259 counting only the distinct ones).
The product of its (nonzero) digits is 27648, while the sum is 36.
The square root of 81640944 is about 9035.5378367865. The cubic root of 81640944 is about 433.8131101576.
The spelling of 81640944 in words is "eighty-one million, six hundred forty thousand, nine hundred forty-four".
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