221838 has 8 divisors (see below), whose sum is σ = 443688. Its totient is φ = 73944.

The previous prime is 221831. The next prime is 221849. The reversal of 221838 is 838122.

221838 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.

221838 is an admirable number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 221838.

It is not an unprimeable number, because it can be changed into a prime (221831) 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, 18481 + ... + 18492.

It is an arithmetic number, because the mean of its divisors is an integer number (55461).

2²²¹⁸³⁸ is an apocalyptic number.

221838 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221838 is a wasteful number, since it uses less digits than its factorization.

221838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36978.

The product of its digits is 768, while the sum is 24.

The square root of 221838 is about 470.9968152759. The cubic root of 221838 is about 60.5357573836.

The spelling of 221838 in words is "two hundred twenty-one thousand, eight hundred thirty-eight".