4243210021 has 2 divisors, whose sum is σ = 4243210022. Its totient is φ = 4243210020.

The previous prime is 4243209973. The next prime is 4243210043. The reversal of 4243210021 is 1200123424.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4161669121 + 81540900 = 64511^2 + 9030^2 .

It is a cyclic number.

It is not a de Polignac number, because 4243210021 - 2¹³ = 4243201829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4243210721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2121605010 + 2121605011.

It is an arithmetic number, because the mean of its divisors is an integer number (2121605011).

Almost surely, 2^4243210021 is an apocalyptic number.

It is an amenable number.

4243210021 is a deficient number, since it is larger than the sum of its proper divisors (1).

4243210021 is an equidigital number, since it uses as much as digits as its factorization.

4243210021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 4243210021 is about 65139.9264737074. The cubic root of 4243210021 is about 1618.9428174663.

Adding to 4243210021 its reverse (1200123424), we get a palindrome (5443333445).

The spelling of 4243210021 in words is "four billion, two hundred forty-three million, two hundred ten thousand, twenty-one".