221281321 has 4 divisors (see below), whose sum is σ = 230902272. Its totient is φ = 211660372.

The previous prime is 221281309. The next prime is 221281327. The reversal of 221281321 is 123182122.

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.

It is a cyclic number.

It is not a de Polignac number, because 221281321 - 2²¹ = 219184169 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221281292 and 221281301.

It is not an unprimeable number, because it can be changed into a prime (221281327) 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, 4810441 + ... + 4810486.

It is an arithmetic number, because the mean of its divisors is an integer number (57725568).

Almost surely, 2^221281321 is an apocalyptic number.

It is an amenable number.

221281321 is a deficient number, since it is larger than the sum of its proper divisors (9620951).

221281321 is an equidigital number, since it uses as much as digits as its factorization.

221281321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9620950.

The product of its digits is 384, while the sum is 22.

The square root of 221281321 is about 14875.5275872824. The cubic root of 221281321 is about 604.8507894220.

The spelling of 221281321 in words is "two hundred twenty-one million, two hundred eighty-one thousand, three hundred twenty-one".