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215305 = 5172149
BaseRepresentation
bin110100100100001001
3101221100021
4310210021
523342210
64340441
71554466
oct644411
9357307
10215305
11137842
12a4721
1376ccc
145866d
1543bda
hex34909

215305 has 12 divisors (see below), whose sum is σ = 276300. Its totient is φ = 161024.

The previous prime is 215297. The next prime is 215309. The reversal of 215305 is 503512.

Adding to 215305 its reverse (503512), we get a palindrome (718817).

It can be written as a sum of positive squares in 6 ways, for example, as 9 + 215296 = 3^2 + 464^2 .

It is not a de Polignac number, because 215305 - 23 = 215297 is a prime.

It is a nialpdrome in base 8.

It is not an unprimeable number, because it can be changed into a prime (215309) 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 11 ways as a sum of consecutive naturals, for example, 1371 + ... + 1519.

It is an arithmetic number, because the mean of its divisors is an integer number (23025).

2215305 is an apocalyptic number.

It is an amenable number.

215305 is a deficient number, since it is larger than the sum of its proper divisors (60995).

215305 is a wasteful number, since it uses less digits than its factorization.

215305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188 (or 171 counting only the distinct ones).

The product of its (nonzero) digits is 150, while the sum is 16.

The square root of 215305 is about 464.0096981745. The cubic root of 215305 is about 59.9355790052.

The spelling of 215305 in words is "two hundred fifteen thousand, three hundred five".

Divisors: 1 5 17 85 149 289 745 1445 2533 12665 43061 215305