4242440021 has 4 divisors (see below), whose sum is σ = 4279983852. Its totient is φ = 4204896192.

The previous prime is 4242440011. The next prime is 4242440029. The reversal of 4242440021 is 1200442424.

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 253128100 + 3989311921 = 15910^2 + 63161^2 .

It is a cyclic number.

It is not a de Polignac number, because 4242440021 - 2²² = 4238245717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4242440029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18771746 + ... + 18771971.

It is an arithmetic number, because the mean of its divisors is an integer number (1069995963).

Almost surely, 2^4242440021 is an apocalyptic number.

It is an amenable number.

4242440021 is a deficient number, since it is larger than the sum of its proper divisors (37543831).

4242440021 is a wasteful number, since it uses less digits than its factorization.

4242440021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37543830.

The product of its (nonzero) digits is 2048, while the sum is 23.

The square root of 4242440021 is about 65134.0158519341. The cubic root of 4242440021 is about 1618.8448836399.

Adding to 4242440021 its reverse (1200442424), we get a palindrome (5442882445).

The spelling of 4242440021 in words is "four billion, two hundred forty-two million, four hundred forty thousand, twenty-one".