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1209 = 31331
BaseRepresentation
bin10010111001
31122210
4102321
514314
65333
73345
oct2271
91583
101209
119aa
12849
13720
14625
15559
hex4b9

1209 has 8 divisors (see below), whose sum is σ = 1792. Its totient is φ = 720.

The previous prime is 1201. The next prime is 1213. The reversal of 1209 is 9021.

Adding to 1209 its sum of digits (12), we get a palindrome (1221).

It can be divided in two parts, 1 and 209, that added together give a triangular number (210 = T20).

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1209 - 23 = 1201 is a prime.

It is a Duffinian number.

1209 is a lucky number.

It is a plaindrome in base 7, base 11 and base 15.

It is a nialpdrome in base 6 and base 13.

It is a junction number, because it is equal to n+sod(n) for n = 1194 and 1203.

It is not an unprimeable number, because it can be changed into a prime (1201) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24 + ... + 54.

It is an arithmetic number, because the mean of its divisors is an integer number (224).

It is an amenable number.

1209 is a deficient number, since it is larger than the sum of its proper divisors (583).

1209 is a wasteful number, since it uses less digits than its factorization.

1209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47.

The product of its (nonzero) digits is 18, while the sum is 12.

The square root of 1209 is about 34.7706773014. The cubic root of 1209 is about 10.6530860153.

The spelling of 1209 in words is "one thousand, two hundred nine".

Divisors: 1 3 13 31 39 93 403 1209