121221220 has 24 divisors (see below), whose sum is σ = 269539704. Its totient is φ = 45636096.

The previous prime is 121221209. The next prime is 121221227. The reversal of 121221220 is 22122121.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 13601344 + 107619876 = 3688^2 + 10374^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 121221220.

It is not an unprimeable number, because it can be changed into a prime (121221227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 177927 + ... + 178606.

It is an arithmetic number, because the mean of its divisors is an integer number (11230821).

Almost surely, 2^121221220 is an apocalyptic number.

121221220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121221220 is an abundant number, since it is smaller than the sum of its proper divisors (148318484).

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

121221220 is a wasteful number, since it uses less digits than its factorization.

121221220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 356559 (or 356557 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 121221220 is about 11010.0508627345. The cubic root of 121221220 is about 494.9099860130.

Adding to 121221220 its reverse (22122121), we get a palindrome (143343341).

Subtracting from 121221220 its reverse (22122121), we obtain a palindrome (99099099).

The spelling of 121221220 in words is "one hundred twenty-one million, two hundred twenty-one thousand, two hundred twenty".