43609021 has 4 divisors (see below), whose sum is σ = 44099100. Its totient is φ = 43118944.

The previous prime is 43608973. The next prime is 43609039. The reversal of 43609021 is 12090634.

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 4995225 + 38613796 = 2235^2 + 6214^2 .

It is a cyclic number.

It is not a de Polignac number, because 43609021 - 2¹⁹ = 43084733 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 (43609061) 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, 244906 + ... + 245083.

It is an arithmetic number, because the mean of its divisors is an integer number (11024775).

Almost surely, 2^43609021 is an apocalyptic number.

It is an amenable number.

43609021 is a deficient number, since it is larger than the sum of its proper divisors (490079).

43609021 is an equidigital number, since it uses as much as digits as its factorization.

43609021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 490078.

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 43609021 is about 6603.7126678861. The cubic root of 43609021 is about 351.9860450950.

Adding to 43609021 its reverse (12090634), we get a palindrome (55699655).

The spelling of 43609021 in words is "forty-three million, six hundred nine thousand, twenty-one".