11000001221 has 6 divisors (see below), whose sum is σ = 12090910566. Its totient is φ = 10000001000.

The previous prime is 11000001209. The next prime is 11000001239. The reversal of 11000001221 is 12210000011.

It can be written as a sum of positive squares in only one way, i.e., 9261945121 + 1738056100 = 96239^2 + 41690^2 .

It is not a de Polignac number, because 11000001221 - 2¹⁴ = 10999984837 is a prime.

It is a Duffinian number.

11000001221 is a modest number, since divided by 1221 gives 11 as remainder.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 11000001199 and 11000001208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11000001121) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 45454430 + ... + 45454671.

It is an arithmetic number, because the mean of its divisors is an integer number (2015151761).

Almost surely, 2^11000001221 is an apocalyptic number.

11000001221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

11000001221 is a deficient number, since it is larger than the sum of its proper divisors (1090909345).

11000001221 is an equidigital number, since it uses as much as digits as its factorization.

11000001221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90909123 (or 90909112 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 11000001221 its reverse (12210000011), we get a palindrome (23210001232).

The spelling of 11000001221 in words is "eleven billion, one thousand, two hundred twenty-one".