4243557221 has 6 divisors (see below), whose sum is σ = 4507862130. Its totient is φ = 3993935936.

The previous prime is 4243557193. The next prime is 4243557257. The reversal of 4243557221 is 1227553424.

It can be written as a sum of positive squares in 3 ways, for example, as 2637952321 + 1605604900 = 51361^2 + 40070^2 .

It is not a de Polignac number, because 4243557221 - 2²⁶ = 4176448357 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 (4243557421) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7341506 + ... + 7342083.

It is an arithmetic number, because the mean of its divisors is an integer number (751310355).

Almost surely, 2^4243557221 is an apocalyptic number.

It is an amenable number.

4243557221 is a deficient number, since it is larger than the sum of its proper divisors (264304909).

4243557221 is a wasteful number, since it uses less digits than its factorization.

4243557221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14683623 (or 14683606 counting only the distinct ones).

The product of its digits is 67200, while the sum is 35.

The square root of 4243557221 is about 65142.5914513692. The cubic root of 4243557221 is about 1618.9869728434.

The spelling of 4243557221 in words is "four billion, two hundred forty-three million, five hundred fifty-seven thousand, two hundred twenty-one".