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287680 = 2652931
BaseRepresentation
bin1000110001111000000
3112121121211
41012033000
533201210
610055504
72305501
oct1061700
9477554
10287680
11187158
1211a594
13a0c33
1476ba8
155a38a
hex463c0

287680 has 56 divisors (see below), whose sum is σ = 731520. Its totient is φ = 107520.

The previous prime is 287671. The next prime is 287681. The reversal of 287680 is 86782.

287680 = T61 + T62 + ... + T124.

287680 is nontrivially palindromic in base 3.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (287681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9265 + ... + 9295.

287680 is a Friedman number, since it can be written as 88^(2+0)+6^7, using all its digits and the basic arithmetic operations.

2287680 is an apocalyptic number.

287680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

287680 is the 310-th octagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 287680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (365760).

287680 is an abundant number, since it is smaller than the sum of its proper divisors (443840).

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

287680 is a wasteful number, since it uses less digits than its factorization.

287680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77 (or 67 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 287680 is about 536.3580893396. The cubic root of 287680 is about 66.0140771931.

The spelling of 287680 in words is "two hundred eighty-seven thousand, six hundred eighty".

Divisors: 1 2 4 5 8 10 16 20 29 31 32 40 58 62 64 80 116 124 145 155 160 232 248 290 310 320 464 496 580 620 899 928 992 1160 1240 1798 1856 1984 2320 2480 3596 4495 4640 4960 7192 8990 9280 9920 14384 17980 28768 35960 57536 71920 143840 287680