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30865 = 56173
BaseRepresentation
bin111100010010001
31120100011
413202101
51441430
6354521
7155662
oct74221
946304
1030865
112120a
1215a41
1311083
14b369
15922a
hex7891

30865 has 4 divisors (see below), whose sum is σ = 37044. Its totient is φ = 24688.

The previous prime is 30859. The next prime is 30869. The reversal of 30865 is 56803.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56803 = 431321.

It can be written as a sum of positive squares in 2 ways, for example, as 3969 + 26896 = 63^2 + 164^2 .

It is a cyclic number.

It is not a de Polignac number, because 30865 - 211 = 28817 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a nialpdrome in base 8.

It is not an unprimeable number, because it can be changed into a prime (30869) 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 3 ways as a sum of consecutive naturals, for example, 3082 + ... + 3091.

It is an arithmetic number, because the mean of its divisors is an integer number (9261).

230865 is an apocalyptic number.

It is an amenable number.

30865 is a deficient number, since it is larger than the sum of its proper divisors (6179).

30865 is an equidigital number, since it uses as much as digits as its factorization.

30865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6178.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 30865 is about 175.6843760839. The cubic root of 30865 is about 31.3681394819.

It can be divided in two parts, 308 and 65, that added together give a palindrome (373).

The spelling of 30865 in words is "thirty thousand, eight hundred sixty-five".

Divisors: 1 5 6173 30865