43666633621 has 4 divisors (see below), whose sum is σ = 47025605452. Its totient is φ = 40307661792.

The previous prime is 43666633589. The next prime is 43666633627. The reversal of 43666633621 is 12633666634.

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 20428984900 + 23237648721 = 142930^2 + 152439^2 .

It is a cyclic number.

It is not a de Polignac number, because 43666633621 - 2⁵ = 43666633589 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 (43666633627) 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, 1679485896 + ... + 1679485921.

It is an arithmetic number, because the mean of its divisors is an integer number (11756401363).

Almost surely, 2^43666633621 is an apocalyptic number.

It is an amenable number.

43666633621 is a deficient number, since it is larger than the sum of its proper divisors (3358971831).

43666633621 is a wasteful number, since it uses less digits than its factorization.

43666633621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3358971830.

The product of its digits is 1679616, while the sum is 46.

The spelling of 43666633621 in words is "forty-three billion, six hundred sixty-six million, six hundred thirty-three thousand, six hundred twenty-one".