43537421 has 4 divisors (see below), whose sum is σ = 43557852. Its totient is φ = 43516992.

The previous prime is 43537409. The next prime is 43537427. The reversal of 43537421 is 12473534.

It is a happy number.

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 41538025 + 1999396 = 6445^2 + 1414^2 .

It is a cyclic number.

It is not a de Polignac number, because 43537421 - 2¹⁸ = 43275277 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 (43537427) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6590 + ... + 11423.

It is an arithmetic number, because the mean of its divisors is an integer number (10889463).

Almost surely, 2^43537421 is an apocalyptic number.

It is an amenable number.

43537421 is a deficient number, since it is larger than the sum of its proper divisors (20431).

43537421 is a wasteful number, since it uses less digits than its factorization.

43537421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20430.

The product of its digits is 10080, while the sum is 29.

The square root of 43537421 is about 6598.2892479794. The cubic root of 43537421 is about 351.7933020517.

The spelling of 43537421 in words is "forty-three million, five hundred thirty-seven thousand, four hundred twenty-one".