4213121221 has 4 divisors (see below), whose sum is σ = 4282188844. Its totient is φ = 4144053600.

The previous prime is 4213121201. The next prime is 4213121243. The reversal of 4213121221 is 1221213124.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 432224100 + 3780897121 = 20790^2 + 61489^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-4213121221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4213121201) 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, 34533720 + ... + 34533841.

It is an arithmetic number, because the mean of its divisors is an integer number (1070547211).

Almost surely, 2^4213121221 is an apocalyptic number.

It is an amenable number.

4213121221 is a deficient number, since it is larger than the sum of its proper divisors (69067623).

4213121221 is an equidigital number, since it uses as much as digits as its factorization.

4213121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69067622.

The product of its digits is 192, while the sum is 19.

The square root of 4213121221 is about 64908.5604600811. The cubic root of 4213121221 is about 1615.1070703199.

Adding to 4213121221 its reverse (1221213124), we get a palindrome (5434334345).

The spelling of 4213121221 in words is "four billion, two hundred thirteen million, one hundred twenty-one thousand, two hundred twenty-one".