2121210221 has 8 divisors (see below), whose sum is σ = 2286685464. Its totient is φ = 1956064320.

The previous prime is 2121210211. The next prime is 2121210227. The reversal of 2121210221 is 1220121212.

It can be written as a sum of positive squares in 4 ways, for example, as 175165225 + 1946044996 = 13235^2 + 44114^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 2121210221 - 2²² = 2117015917 is a prime.

It is a super-3 number, since 3×2121210221³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2121210196 and 2121210205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121210227) 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, 68870 + ... + 94791.

It is an arithmetic number, because the mean of its divisors is an integer number (285835683).

Almost surely, 2^2121210221 is an apocalyptic number.

It is an amenable number.

2121210221 is a deficient number, since it is larger than the sum of its proper divisors (165475243).

2121210221 is a wasteful number, since it uses less digits than its factorization.

2121210221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164671.

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

The square root of 2121210221 is about 46056.5980180907. The cubic root of 2121210221 is about 1284.8760590438.

Adding to 2121210221 its reverse (1220121212), we get a palindrome (3341331433).

The spelling of 2121210221 in words is "two billion, one hundred twenty-one million, two hundred ten thousand, two hundred twenty-one".