2120121221 has 8 divisors (see below), whose sum is σ = 2247623640. Its totient is φ = 1992928768.

The previous prime is 2120121197. The next prime is 2120121233. The reversal of 2120121221 is 1221210212.

It can be written as a sum of positive squares in 4 ways, for example, as 312936100 + 1807185121 = 17690^2 + 42511^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-2120121221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2120121196 and 2120121205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2120123221) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 63326 + ... + 90831.

It is an arithmetic number, because the mean of its divisors is an integer number (280952955).

Almost surely, 2^2120121221 is an apocalyptic number.

It is an amenable number.

2120121221 is a deficient number, since it is larger than the sum of its proper divisors (127502419).

2120121221 is a wasteful number, since it uses less digits than its factorization.

2120121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154983.

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 2120121221 is about 46044.7740900094. The cubic root of 2120121221 is about 1284.6561422040.

Adding to 2120121221 its reverse (1221210212), we get a palindrome (3341331433).

The spelling of 2120121221 in words is "two billion, one hundred twenty million, one hundred twenty-one thousand, two hundred twenty-one".