43421165621 has 8 divisors (see below), whose sum is σ = 45985944024. Its totient is φ = 40857564160.

The previous prime is 43421165611. The next prime is 43421165659. The reversal of 43421165621 is 12656112434.

It can be written as a sum of positive squares in 4 ways, for example, as 18792571396 + 24628594225 = 137086^2 + 156935^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-43421165621 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 (43421165611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 217700 + ... + 366381.

It is an arithmetic number, because the mean of its divisors is an integer number (5748243003).

Almost surely, 2^43421165621 is an apocalyptic number.

It is an amenable number.

43421165621 is a deficient number, since it is larger than the sum of its proper divisors (2564778403).

43421165621 is a wasteful number, since it uses less digits than its factorization.

43421165621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 588471.

The product of its digits is 34560, while the sum is 35.

The spelling of 43421165621 in words is "forty-three billion, four hundred twenty-one million, one hundred sixty-five thousand, six hundred twenty-one".