219921 has 8 divisors (see below), whose sum is σ = 315840. Its totient is φ = 135312.

The previous prime is 219917. The next prime is 219931. The reversal of 219921 is 129912.

219921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 219921 - 2² = 219917 is a prime.

219921 is a lucky number.

It is a nialpdrome in base 8.

It is a junction number, because it is equal to n+sod(n) for n = 219891 and 219900.

It is not an unprimeable number, because it can be changed into a prime (219911) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2781 + ... + 2858.

It is an arithmetic number, because the mean of its divisors is an integer number (39480).

2²¹⁹⁹²¹ is an apocalyptic number.

It is an amenable number.

219921 is a deficient number, since it is larger than the sum of its proper divisors (95919).

219921 is a wasteful number, since it uses less digits than its factorization.

219921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5655.

The product of its digits is 324, while the sum is 24.

The square root of 219921 is about 468.9573541379. The cubic root of 219921 is about 60.3608806234.

Subtracting from 219921 its reverse (129912), we obtain a palindrome (90009).

The spelling of 219921 in words is "two hundred nineteen thousand, nine hundred twenty-one".