819121 has 4 divisors (see below), whose sum is σ = 822052. Its totient is φ = 816192.

The previous prime is 819101. The next prime is 819131. The reversal of 819121 is 121918.

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

It can be written as a sum of positive squares in 2 ways, for example, as 378225 + 440896 = 615^2 + 664^2 .

It is a cyclic number.

It is not a de Polignac number, because 819121 - 2¹¹ = 817073 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 819092 and 819101.

It is not an unprimeable number, because it can be changed into a prime (819101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 996 + ... + 1621.

It is an arithmetic number, because the mean of its divisors is an integer number (205513).

2⁸¹⁹¹²¹ is an apocalyptic number.

It is an amenable number.

819121 is a deficient number, since it is larger than the sum of its proper divisors (2931).

819121 is a wasteful number, since it uses less digits than its factorization.

819121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2930.

The product of its digits is 144, while the sum is 22.

The square root of 819121 is about 905.0530371199. The cubic root of 819121 is about 93.5655597475.

It can be divided in two parts, 819 and 121, that multiplied together give a palindrome (99099).

The spelling of 819121 in words is "eight hundred nineteen thousand, one hundred twenty-one".