2121231221 has 8 divisors (see below), whose sum is σ = 2131035480. Its totient is φ = 2111444992.

The previous prime is 2121231197. The next prime is 2121231223. The reversal of 2121231221 is 1221321212.

It can be written as a sum of positive squares in 4 ways, for example, as 794450596 + 1326780625 = 28186^2 + 36425^2 .

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 2121231221 - 2¹⁰ = 2121230197 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2121231221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121231223) 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, 268301 + ... + 276093.

It is an arithmetic number, because the mean of its divisors is an integer number (266379435).

Almost surely, 2^2121231221 is an apocalyptic number.

It is an amenable number.

2121231221 is a deficient number, since it is larger than the sum of its proper divisors (9804259).

2121231221 is an equidigital number, since it uses as much as digits as its factorization.

2121231221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9015.

The product of its digits is 96, while the sum is 17.

The square root of 2121231221 is about 46056.8259978909. The cubic root of 2121231221 is about 1284.8802991246.

Adding to 2121231221 its reverse (1221321212), we get a palindrome (3342552433).

The spelling of 2121231221 in words is "two billion, one hundred twenty-one million, two hundred thirty-one thousand, two hundred twenty-one".