1001221220 has 12 divisors (see below), whose sum is σ = 2102564604. Its totient is φ = 400488480.

The previous prime is 1001221187. The next prime is 1001221223. The reversal of 1001221220 is 221221001.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 164044864 + 837176356 = 12808^2 + 28934^2 .

It is not an unprimeable number, because it can be changed into a prime (1001221223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25030511 + ... + 25030550.

It is an arithmetic number, because the mean of its divisors is an integer number (175213717).

Almost surely, 2^1001221220 is an apocalyptic number.

1001221220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1001221220 is an abundant number, since it is smaller than the sum of its proper divisors (1101343384).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1001221220 is a wasteful number, since it uses less digits than its factorization.

1001221220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50061070 (or 50061068 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 1001221220 is about 31642.0798937112. The cubic root of 1001221220 is about 1000.4069077370.

Adding to 1001221220 its reverse (221221001), we get a palindrome (1222442221).

The spelling of 1001221220 in words is "one billion, one million, two hundred twenty-one thousand, two hundred twenty".