Search a number
-
+
638820 = 223357132
BaseRepresentation
bin10011011111101100100
31012110022000
42123331210
5130420240
621405300
75300310
oct2337544
91173260
10638820
113a6a56
12269830
13194a00
14128b40
15c9430
hex9bf64

638820 has 144 divisors (see below), whose sum is σ = 2459520. Its totient is φ = 134784.

The previous prime is 638819. The next prime is 638839. The reversal of 638820 is 28836.

638820 is a `hidden beast` number, since 638 + 8 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nialpdrome in base 15.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 49134 + ... + 49146.

It is an arithmetic number, because the mean of its divisors is an integer number (17080).

2638820 is an apocalyptic number.

638820 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 638820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1229760).

638820 is an abundant number, since it is smaller than the sum of its proper divisors (1820700).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

638820 is a wasteful number, since it uses less digits than its factorization.

638820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51 (or 30 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 638820 is about 799.2621597448. The cubic root of 638820 is about 86.1243918315.

The spelling of 638820 in words is "six hundred thirty-eight thousand, eight hundred twenty".

Divisors: 1 2 3 4 5 6 7 9 10 12 13 14 15 18 20 21 26 27 28 30 35 36 39 42 45 52 54 60 63 65 70 78 84 90 91 105 108 117 126 130 135 140 156 169 180 182 189 195 210 234 252 260 270 273 315 338 351 364 378 390 420 455 468 507 540 546 585 630 676 702 756 780 819 845 910 945 1014 1092 1170 1183 1260 1365 1404 1521 1638 1690 1755 1820 1890 2028 2340 2366 2457 2535 2730 3042 3276 3380 3510 3549 3780 4095 4563 4732 4914 5070 5460 5915 6084 7020 7098 7605 8190 9126 9828 10140 10647 11830 12285 14196 15210 16380 17745 18252 21294 22815 23660 24570 30420 31941 35490 42588 45630 49140 53235 63882 70980 91260 106470 127764 159705 212940 319410 638820