1311221 has 4 divisors (see below), whose sum is σ = 1343244. Its totient is φ = 1279200.

The previous prime is 1311217. The next prime is 1311223. The reversal of 1311221 is 1221131.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 70225 + 1240996 = 265^2 + 1114^2 .

It is not a de Polignac number, because 1311221 - 2² = 1311217 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1311223) 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, 15950 + ... + 16031.

It is an arithmetic number, because the mean of its divisors is an integer number (335811).

2^1311221 is an apocalyptic number.

It is an amenable number.

1311221 is a deficient number, since it is larger than the sum of its proper divisors (32023).

1311221 is an equidigital number, since it uses as much as digits as its factorization.

1311221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32022.

The product of its digits is 12, while the sum is 11.

The square root of 1311221 is about 1145.0855863210. The cubic root of 1311221 is about 109.4524024626.

Adding to 1311221 its reverse (1221131), we get a palindrome (2532352).

It can be divided in two parts, 131 and 1221, that multiplied together give a palindrome (159951).

The spelling of 1311221 in words is "one million, three hundred eleven thousand, two hundred twenty-one".