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28709 = 191511
BaseRepresentation
bin111000000100101
31110101022
413000211
51404314
6340525
7146462
oct70045
943338
1028709
111a62a
1214745
13100b5
14a669
15878e
hex7025

28709 has 4 divisors (see below), whose sum is σ = 30240. Its totient is φ = 27180.

The previous prime is 28703. The next prime is 28711. The reversal of 28709 is 90782.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2k-28709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28703) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 737 + ... + 774.

It is an arithmetic number, because the mean of its divisors is an integer number (7560).

228709 is an apocalyptic number.

It is an amenable number.

28709 is a deficient number, since it is larger than the sum of its proper divisors (1531).

28709 is a wasteful number, since it uses less digits than its factorization.

28709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1530.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 28709 is about 169.4373040390. The cubic root of 28709 is about 30.6200589002.

It can be divided in two parts, 28 and 709, that added together give a palindrome (737).

The spelling of 28709 in words is "twenty-eight thousand, seven hundred nine".

Divisors: 1 19 1511 28709