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BaseRepresentation
bin11010101
321220
43111
51323
6553
7423
oct325
9256
10213
11184
12159
13135
14113
15e3
hexd5

213 has 4 divisors (see below), whose sum is σ = 288. Its totient is φ = 140.

The previous prime is 211. The next prime is 223. The reversal of 213 is 312.

Adding to 213 its reverse (312), we get a palindrome (525).

Subtracting 213 from its reverse (312), we obtain a palindrome (99).

It can be divided in two parts, 2 and 13, that added together give a triangular number (15 = T5).

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 not a de Polignac number, because 213 - 21 = 211 is a prime.

It is a D-number.

It is a plaindrome in base 9, base 12, base 13 and base 14.

It is a nialpdrome in base 4, base 6, base 15 and base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211) 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, 33 + ... + 38.

It is an arithmetic number, because the mean of its divisors is an integer number (72).

It is an amenable number.

213 is a deficient number, since it is larger than the sum of its proper divisors (75).

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

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

The sum of its prime factors is 74.

The product of its digits is 6, while the sum is 6.

The square root of 213 is about 14.5945195193. The cubic root of 213 is about 5.9720926198.

The spelling of 213 in words is "two hundred thirteen", and thus it is an aban number.

Divisors: 1 3 71 213