1221321 has 8 divisors (see below), whose sum is σ = 1633984. Its totient is φ = 811440.

The previous prime is 1221299. The next prime is 1221373. The reversal of 1221321 is 1231221.

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

It is not a de Polignac number, because 1221321 - 2⁵ = 1221289 is a prime.

It is a Duffinian number.

1221321 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1221297 and 1221306.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221391) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 780 + ... + 1746.

It is an arithmetic number, because the mean of its divisors is an integer number (204248).

2^1221321 is an apocalyptic number.

It is an amenable number.

1221321 is a deficient number, since it is larger than the sum of its proper divisors (412663).

1221321 is an equidigital number, since it uses as much as digits as its factorization.

1221321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1391.

The product of its digits is 24, while the sum is 12.

The square root of 1221321 is about 1105.1339285354. The cubic root of 1221321 is about 106.8915254362.

Adding to 1221321 its reverse (1231221), we get a palindrome (2452542).

The spelling of 1221321 in words is "one million, two hundred twenty-one thousand, three hundred twenty-one".