227821 has 8 divisors (see below), whose sum is σ = 252000. Its totient is φ = 204240.

The previous prime is 227797. The next prime is 227827. The reversal of 227821 is 128722.

227821 = T₁₉₈ + T₁₉₉ + ... + T₂₀₈.

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

It is a cyclic number.

It is not a de Polignac number, because 227821 - 2⁵ = 227789 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 227792 and 227801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (227827) 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 7 ways as a sum of consecutive naturals, for example, 1455 + ... + 1603.

It is an arithmetic number, because the mean of its divisors is an integer number (31500).

2²²⁷⁸²¹ is an apocalyptic number.

It is an amenable number.

227821 is a deficient number, since it is larger than the sum of its proper divisors (24179).

227821 is a wasteful number, since it uses less digits than its factorization.

227821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 299.

The product of its digits is 448, while the sum is 22.

The square root of 227821 is about 477.3059815255. The cubic root of 227821 is about 61.0751559541.

Subtracting from 227821 its reverse (128722), we obtain a palindrome (99099).

The spelling of 227821 in words is "two hundred twenty-seven thousand, eight hundred twenty-one".