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51209 = 411249
BaseRepresentation
bin1100100000001001
32121020122
430200021
53114314
61033025
7302204
oct144011
977218
1051209
1135524
1225775
131a402
141493b
151028e
hexc809

51209 has 4 divisors (see below), whose sum is σ = 52500. Its totient is φ = 49920.

The previous prime is 51203. The next prime is 51217. The reversal of 51209 is 90215.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90215 = 518043.

It can be written as a sum of positive squares in 2 ways, for example, as 10000 + 41209 = 100^2 + 203^2 .

It is a cyclic number.

It is not a de Polignac number, because 51209 - 24 = 51193 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 (51203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 584 + ... + 665.

It is an arithmetic number, because the mean of its divisors is an integer number (13125).

251209 is an apocalyptic number.

It is an amenable number.

51209 is a deficient number, since it is larger than the sum of its proper divisors (1291).

51209 is a wasteful number, since it uses less digits than its factorization.

51209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1290.

The product of its (nonzero) digits is 90, while the sum is 17.

The square root of 51209 is about 226.2940564840. The cubic root of 51209 is about 37.1348862862.

The spelling of 51209 in words is "fifty-one thousand, two hundred nine".

Divisors: 1 41 1249 51209