| Base | Representation |
|---|---|
| bin | 100110011010001… |
| … | …010110100000000 |
| 3 | 1122220112121201100 |
| 4 | 212122022310000 |
| 5 | 2304431103430 |
| 6 | 143535334400 |
| 7 | 21653155260 |
| oct | 4632126400 |
| 9 | 1586477640 |
| 10 | 644394240 |
| 11 | 30081aa26 |
| 12 | 15b981400 |
| 13 | a3670589 |
| 14 | 618217a0 |
| 15 | 3b88b960 |
| hex | 2668ad00 |
644394240 has 432 divisors, whose sum is σ = 2609582976. Its totient is φ = 143769600.
The previous prime is 644394229. The next prime is 644394251. The reversal of 644394240 is 42493446.
644394240 is a `hidden beast` number, since 644 + 3 + 9 + 4 + 2 + 4 + 0 = 666.
It is an interprime number because it is at equal distance from previous prime (644394229) and next prime (644394251).
It is a super-5 number, since 5×6443942405 (a number of 45 digits) contains 55555 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 = 644394195 and 644394204.
It is a congruent number.
It is an unprimeable number.
It is a pernicious number, because its binary representation contains a prime number (11) of ones.
It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4918975 + ... + 4919105.
Almost surely, 2644394240 is an apocalyptic number.
644394240 is a gapful number since it is divisible by the number (60) 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 644394240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1304791488).
644394240 is an abundant number, since it is smaller than the sum of its proper divisors (1965188736).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
644394240 is a wasteful number, since it uses less digits than its factorization.
644394240 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 226 (or 209 counting only the distinct ones).
The product of its (nonzero) digits is 82944, while the sum is 36.
The square root of 644394240 is about 25384.9215086437. The cubic root of 644394240 is about 863.7416923295.
The spelling of 644394240 in words is "six hundred forty-four million, three hundred ninety-four thousand, two hundred forty".
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