11311221 has 8 divisors (see below), whose sum is σ = 15104320. Its totient is φ = 7529472.

The previous prime is 11311219. The next prime is 11311231. The reversal of 11311221 is 12211311.

11311221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 11311221 - 2¹ = 11311219 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 11311197 and 11311206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11311231) 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, 145 + ... + 4758.

It is an arithmetic number, because the mean of its divisors is an integer number (1888040).

Almost surely, 2^11311221 is an apocalyptic number.

It is an amenable number.

11311221 is a deficient number, since it is larger than the sum of its proper divisors (3793099).

11311221 is an equidigital number, since it uses as much as digits as its factorization.

11311221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5675.

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

The square root of 11311221 is about 3363.2158717513. The cubic root of 11311221 is about 224.4759557122.

Adding to 11311221 its reverse (12211311), we get a palindrome (23522532).

The spelling of 11311221 in words is "eleven million, three hundred eleven thousand, two hundred twenty-one".