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218028380 = 225291991889
BaseRepresentation
bin11001111111011…
…01100101011100
3120012020222201012
430333231211130
5421303402010
633345034352
75255132153
oct1477554534
9505228635
10218028380
11102086a49
12610259b8
133622a19b
1420d5659a
151421b005
hexcfed95c

218028380 has 48 divisors (see below), whose sum is σ = 476280000. Its totient is φ = 83736576.

The previous prime is 218028367. The next prime is 218028403. The reversal of 218028380 is 83820812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 114476 + ... + 116364.

It is an arithmetic number, because the mean of its divisors is an integer number (9922500).

Almost surely, 2218028380 is an apocalyptic number.

218028380 is a gapful number since it is divisible by the number (20) 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 218028380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (238140000).

218028380 is an abundant number, since it is smaller than the sum of its proper divisors (258251620).

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

218028380 is a wasteful number, since it uses less digits than its factorization.

218028380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2126 (or 2124 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 32.

The square root of 218028380 is about 14765.7840970265. The cubic root of 218028380 is about 601.8722811581.

The spelling of 218028380 in words is "two hundred eighteen million, twenty-eight thousand, three hundred eighty".

Divisors: 1 2 4 5 10 20 29 58 116 145 199 290 398 580 796 995 1889 1990 3778 3980 5771 7556 9445 11542 18890 23084 28855 37780 54781 57710 109562 115420 219124 273905 375911 547810 751822 1095620 1503644 1879555 3759110 7518220 10901419 21802838 43605676 54507095 109014190 218028380