4243331021 has 2 divisors, whose sum is σ = 4243331022. Its totient is φ = 4243331020.

The previous prime is 4243330981. The next prime is 4243331101. The reversal of 4243331021 is 1201333424.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2233602121 + 2009728900 = 47261^2 + 44830^2 .

It is a cyclic number.

It is not a de Polignac number, because 4243331021 - 2¹⁸ = 4243068877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4243331321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2121665510 + 2121665511.

It is an arithmetic number, because the mean of its divisors is an integer number (2121665511).

Almost surely, 2^4243331021 is an apocalyptic number.

It is an amenable number.

4243331021 is a deficient number, since it is larger than the sum of its proper divisors (1).

4243331021 is an equidigital number, since it uses as much as digits as its factorization.

4243331021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 23.

The square root of 4243331021 is about 65140.8552369402. The cubic root of 4243331021 is about 1618.9582059904.

Adding to 4243331021 its reverse (1201333424), we get a palindrome (5444664445).

The spelling of 4243331021 in words is "four billion, two hundred forty-three million, three hundred thirty-one thousand, twenty-one".