81219 has 4 divisors (see below), whose sum is σ = 108296. Its totient is φ = 54144.

The previous prime is 81203. The next prime is 81223. The reversal of 81219 is 91218.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 81219 - 2⁴ = 81203 is a prime.

It is a super-2 number, since 2×81219² = 13193051922, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81195 and 81204.

It is not an unprimeable number, because it can be changed into a prime (81239) 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, 13534 + ... + 13539.

It is an arithmetic number, because the mean of its divisors is an integer number (27074).

2⁸¹²¹⁹ is an apocalyptic number.

81219 is a deficient number, since it is larger than the sum of its proper divisors (27077).

81219 is a wasteful number, since it uses less digits than its factorization.

81219 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27076.

The product of its digits is 144, while the sum is 21.

The square root of 81219 is about 284.9894734898. The cubic root of 81219 is about 43.3064461741.

Subtracting 81219 from its reverse (91218), we obtain a palindrome (9999).

It can be divided in two parts, 81 and 219, that added together give a triangular number (300 = T₂₄).

The spelling of 81219 in words is "eighty-one thousand, two hundred nineteen".