281221 has 4 divisors (see below), whose sum is σ = 293472. Its totient is φ = 268972.

The previous prime is 281207. The next prime is 281227. The reversal of 281221 is 122182.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 122182 = 2 ⋅61091.

It is a cyclic number.

It is not a de Polignac number, because 281221 - 2⁵ = 281189 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 281195 and 281204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (281227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6091 + ... + 6136.

It is an arithmetic number, because the mean of its divisors is an integer number (73368).

2²⁸¹²²¹ is an apocalyptic number.

It is an amenable number.

281221 is a deficient number, since it is larger than the sum of its proper divisors (12251).

281221 is a wasteful number, since it uses less digits than its factorization.

281221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12250.

The product of its digits is 64, while the sum is 16.

The square root of 281221 is about 530.3027437229. The cubic root of 281221 is about 65.5162828815.

The spelling of 281221 in words is "two hundred eighty-one thousand, two hundred twenty-one".