43216521 has 4 divisors (see below), whose sum is σ = 57622032. Its totient is φ = 28811012.

The previous prime is 43216489. The next prime is 43216627. The reversal of 43216521 is 12561234.

43216521 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 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 43216521 - 2⁵ = 43216489 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 43216491 and 43216500.

It is not an unprimeable number, because it can be changed into a prime (43216721) 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, 7202751 + ... + 7202756.

It is an arithmetic number, because the mean of its divisors is an integer number (14405508).

Almost surely, 2^43216521 is an apocalyptic number.

It is an amenable number.

43216521 is a deficient number, since it is larger than the sum of its proper divisors (14405511).

43216521 is a wasteful number, since it uses less digits than its factorization.

43216521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14405510.

The product of its digits is 1440, while the sum is 24.

The square root of 43216521 is about 6573.9273649775. The cubic root of 43216521 is about 350.9268522339.

Adding to 43216521 its reverse (12561234), we get a palindrome (55777755).

The spelling of 43216521 in words is "forty-three million, two hundred sixteen thousand, five hundred twenty-one".