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BaseRepresentation
bin10010111111
31200000
4102333
514330
65343
73354
oct2277
91600
101215
11a05
12853
13726
1462b
15560
hex4bf

1215 has 12 divisors (see below), whose sum is σ = 2184. Its totient is φ = 648.

The previous prime is 1213. The next prime is 1217. The reversal of 1215 is 5121.

Adding to 1215 its product of digits (10), we get a triangular number (1225 = T49).

Adding to 1215 its reverse (5121), we get a palindrome (6336).

It can be divided in two parts, 12 and 15, that added together give a cube (27 = 33).

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1213) and next prime (1217).

It is an ABA number since it can be written as A⋅BA, here for A=5, B=3.

It is not a de Polignac number, because 1215 - 21 = 1213 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a plaindrome in base 8 and base 16.

It is a nialpdrome in base 12.

It is a zygodrome in base 8.

It is a junction number, because it is equal to n+sod(n) for n = 1197 and 1206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 241 + ... + 245.

It is an arithmetic number, because the mean of its divisors is an integer number (182).

1215 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1215 is a deficient number, since it is larger than the sum of its proper divisors (969).

1215 is an frugal number, since it uses more digits than its factorization.

1215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20 (or 8 counting only the distinct ones).

The product of its digits is 10, while the sum is 9.

The square root of 1215 is about 34.8568501159. The cubic root of 1215 is about 10.6706799135.

The spelling of 1215 in words is "one thousand, two hundred fifteen".

Divisors: 1 3 5 9 15 27 45 81 135 243 405 1215