1328221 has 4 divisors (see below), whose sum is σ = 1342012. Its totient is φ = 1314432.

The previous prime is 1328219. The next prime is 1328231. The reversal of 1328221 is 1228231.

It is the 471-st star number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1228231 = 211 ⋅5821.

It can be written as a sum of positive squares in 2 ways, for example, as 1092025 + 236196 = 1045^2 + 486^2 .

It is a cyclic number.

It is not a de Polignac number, because 1328221 - 2¹ = 1328219 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1328231) 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, 6750 + ... + 6943.

It is an arithmetic number, because the mean of its divisors is an integer number (335503).

2^1328221 is an apocalyptic number.

It is an amenable number.

1328221 is a deficient number, since it is larger than the sum of its proper divisors (13791).

1328221 is an equidigital number, since it uses as much as digits as its factorization.

1328221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13790.

The product of its digits is 192, while the sum is 19.

The square root of 1328221 is about 1152.4847070569. The cubic root of 1328221 is about 109.9233901834.

The spelling of 1328221 in words is "one million, three hundred twenty-eight thousand, two hundred twenty-one".