43987321 has 4 divisors (see below), whose sum is σ = 50271232. Its totient is φ = 37703412.

The previous prime is 43987319. The next prime is 43987327. The reversal of 43987321 is 12378934.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 43987321 - 2¹ = 43987319 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (43987327) 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, 3141945 + ... + 3141958.

It is an arithmetic number, because the mean of its divisors is an integer number (12567808).

Almost surely, 2^43987321 is an apocalyptic number.

It is an amenable number.

43987321 is a deficient number, since it is larger than the sum of its proper divisors (6283911).

43987321 is an equidigital number, since it uses as much as digits as its factorization.

43987321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6283910.

The product of its digits is 36288, while the sum is 37.

The square root of 43987321 is about 6632.2937962669. The cubic root of 43987321 is about 353.0009202094. Note that the first 3 decimals are identical.

The spelling of 43987321 in words is "forty-three million, nine hundred eighty-seven thousand, three hundred twenty-one".