43688621 has 4 divisors (see below), whose sum is σ = 43725852. Its totient is φ = 43651392.

The previous prime is 43688611. The next prime is 43688639. The reversal of 43688621 is 12688634.

It is a happy number.

43688621 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.

It can be written as a sum of positive squares in 2 ways, for example, as 10176100 + 33512521 = 3190^2 + 5789^2 .

It is a cyclic number.

It is not a de Polignac number, because 43688621 - 2¹⁸ = 43426477 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 (43688611) 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, 16796 + ... + 19221.

It is an arithmetic number, because the mean of its divisors is an integer number (10931463).

Almost surely, 2^43688621 is an apocalyptic number.

It is an amenable number.

43688621 is a deficient number, since it is larger than the sum of its proper divisors (37231).

43688621 is a wasteful number, since it uses less digits than its factorization.

43688621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37230.

The product of its digits is 55296, while the sum is 38.

The square root of 43688621 is about 6609.7368328853. The cubic root of 43688621 is about 352.2000761875.

The spelling of 43688621 in words is "forty-three million, six hundred eighty-eight thousand, six hundred twenty-one".