2121021220 has 12 divisors (see below), whose sum is σ = 4454144604. Its totient is φ = 848408480.

The previous prime is 2121021197. The next prime is 2121021223. The reversal of 2121021220 is 221201212.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 245611584 + 1875409636 = 15672^2 + 43306^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 2121021220.

It is not an unprimeable number, because it can be changed into a prime (2121021223) 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, 53025511 + ... + 53025550.

It is an arithmetic number, because the mean of its divisors is an integer number (371178717).

Almost surely, 2^2121021220 is an apocalyptic number.

2121021220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2121021220 is an abundant number, since it is smaller than the sum of its proper divisors (2333123384).

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

2121021220 is a wasteful number, since it uses less digits than its factorization.

2121021220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106051070 (or 106051068 counting only the distinct ones).

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

The square root of 2121021220 is about 46054.5461382479. The cubic root of 2121021220 is about 1284.8378968553.

Adding to 2121021220 its reverse (221201212), we get a palindrome (2342222432).

The spelling of 2121021220 in words is "two billion, one hundred twenty-one million, twenty-one thousand, two hundred twenty".