Search a number
-
+
81217 = 241337
BaseRepresentation
bin10011110101000001
311010102001
4103311001
510044332
61424001
7455533
oct236501
9133361
1081217
1156024
123b001
132ac76
1421853
15190e7
hex13d41

81217 has 4 divisors (see below), whose sum is σ = 81796. Its totient is φ = 80640.

The previous prime is 81203. The next prime is 81223. The reversal of 81217 is 71218.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 41616 + 39601 = 204^2 + 199^2 .

It is a cyclic number.

It is not a de Polignac number, because 81217 - 215 = 48449 is a prime.

It is a Duffinian number.

81217 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 81194 and 81203.

It is not an unprimeable number, because it can be changed into a prime (81017) 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, 73 + ... + 409.

It is an arithmetic number, because the mean of its divisors is an integer number (20449).

281217 is an apocalyptic number.

It is an amenable number.

81217 is a deficient number, since it is larger than the sum of its proper divisors (579).

81217 is a wasteful number, since it uses less digits than its factorization.

81217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 578.

The product of its digits is 112, while the sum is 19.

The square root of 81217 is about 284.9859645667. The cubic root of 81217 is about 43.3060907006.

Subtracting from 81217 its reverse (71218), we obtain a palindrome (9999).

It can be divided in two parts, 8121 and 7, that added together give a triangular number (8128 = T127).

The spelling of 81217 in words is "eighty-one thousand, two hundred seventeen".

Divisors: 1 241 337 81217