4221212021 has 4 divisors (see below), whose sum is σ = 4545920652. Its totient is φ = 3896503392.

The previous prime is 4221211993. The next prime is 4221212027. The reversal of 4221212021 is 1202121224.

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 453093796 + 3768118225 = 21286^2 + 61385^2 .

It is a cyclic number.

It is not a de Polignac number, because 4221212021 - 2¹⁰ = 4221210997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4221212027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 162354296 + ... + 162354321.

It is an arithmetic number, because the mean of its divisors is an integer number (1136480163).

Almost surely, 2^4221212021 is an apocalyptic number.

It is an amenable number.

4221212021 is a deficient number, since it is larger than the sum of its proper divisors (324708631).

4221212021 is a wasteful number, since it uses less digits than its factorization.

4221212021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 324708630.

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 4221212021 is about 64970.8551659896. The cubic root of 4221212021 is about 1616.1402831207.

Adding to 4221212021 its reverse (1202121224), we get a palindrome (5423333245).

The spelling of 4221212021 in words is "four billion, two hundred twenty-one million, two hundred twelve thousand, twenty-one".