11101221 has 36 divisors (see below), whose sum is σ = 17778852. Its totient is φ = 6649344.

The previous prime is 11101217. The next prime is 11101231. The reversal of 11101221 is 12210111.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 4796100 + 6305121 = 2190^2 + 2511^2 .

It is not a de Polignac number, because 11101221 - 2² = 11101217 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

11101221 is a modest number, since divided by 1221 gives 1110 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11101231) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 209431 + ... + 209483.

It is an arithmetic number, because the mean of its divisors is an integer number (493857).

Almost surely, 2^11101221 is an apocalyptic number.

It is an amenable number.

11101221 is a deficient number, since it is larger than the sum of its proper divisors (6677631).

11101221 is a wasteful number, since it uses less digits than its factorization.

11101221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150 (or 110 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

The square root of 11101221 is about 3331.8494863964. The cubic root of 11101221 is about 223.0780893777.

Adding to 11101221 its reverse (12210111), we get a palindrome (23311332).

The spelling of 11101221 in words is "eleven million, one hundred one thousand, two hundred twenty-one".