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680805 = 345412
BaseRepresentation
bin10100110001101100101
31021120220000
42212031211
5133241210
622331513
75533566
oct2461545
91246800
10680805
11425554
12289b99
131aab58
1413a16d
15d6ac0
hexa6365

680805 has 30 divisors (see below), whose sum is σ = 1250898. Its totient is φ = 354240.

The previous prime is 680803. The next prime is 680809. The reversal of 680805 is 508086.

680805 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 3 ways, for example, as 39204 + 641601 = 198^2 + 801^2 .

It is not a de Polignac number, because 680805 - 21 = 680803 is a prime.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (680803) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 16585 + ... + 16625.

2680805 is an apocalyptic number.

It is an amenable number.

680805 is a deficient number, since it is larger than the sum of its proper divisors (570093).

680805 is an equidigital number, since it uses as much as digits as its factorization.

680805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99 (or 49 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 680805 is about 825.1090836974. The cubic root of 680805 is about 87.9712802286.

It can be divided in two parts, 680 and 805, that added together give a triangular number (1485 = T54).

The spelling of 680805 in words is "six hundred eighty thousand, eight hundred five".

Divisors: 1 3 5 9 15 27 41 45 81 123 135 205 369 405 615 1107 1681 1845 3321 5043 5535 8405 15129 16605 25215 45387 75645 136161 226935 680805