11281221 has 24 divisors (see below), whose sum is σ = 19443840. Its totient is φ = 6445656.

The previous prime is 11281211. The next prime is 11281243. The reversal of 11281221 is 12218211.

It is not a de Polignac number, because 11281221 - 2¹³ = 11273029 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 11281194 and 11281203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11281211) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2941 + ... + 5586.

It is an arithmetic number, because the mean of its divisors is an integer number (810160).

Almost surely, 2^11281221 is an apocalyptic number.

It is an amenable number.

11281221 is a deficient number, since it is larger than the sum of its proper divisors (8162619).

11281221 is an equidigital number, since it uses as much as digits as its factorization.

11281221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8550 (or 8537 counting only the distinct ones).

The product of its digits is 64, while the sum is 18.

The square root of 11281221 is about 3358.7528935603. The cubic root of 11281221 is about 224.2773257828.

Adding to 11281221 its reverse (12218211), we get a palindrome (23499432).

The spelling of 11281221 in words is "eleven million, two hundred eighty-one thousand, two hundred twenty-one".