43542421 has 4 divisors (see below), whose sum is σ = 46891852. Its totient is φ = 40192992.

The previous prime is 43542409. The next prime is 43542431. The reversal of 43542421 is 12424534.

It is a happy number.

43542421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12424534 = 2 ⋅6212267.

It can be written as a sum of positive squares in 2 ways, for example, as 24059025 + 19483396 = 4905^2 + 4414^2 .

It is a cyclic number.

It is not a de Polignac number, because 43542421 - 2⁷ = 43542293 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 (43542431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1674696 + ... + 1674721.

It is an arithmetic number, because the mean of its divisors is an integer number (11722963).

Almost surely, 2^43542421 is an apocalyptic number.

It is an amenable number.

43542421 is a deficient number, since it is larger than the sum of its proper divisors (3349431).

43542421 is a wasteful number, since it uses less digits than its factorization.

43542421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3349430.

The product of its digits is 3840, while the sum is 25.

The square root of 43542421 is about 6598.6681231897. The cubic root of 43542421 is about 351.8067686217.

Adding to 43542421 its reverse (12424534), we get a palindrome (55966955).

The spelling of 43542421 in words is "forty-three million, five hundred forty-two thousand, four hundred twenty-one".