43666649 has 4 divisors (see below), whose sum is σ = 47025636. Its totient is φ = 40307664.

The previous prime is 43666639. The next prime is 43666657. The reversal of 43666649 is 94666634.

43666649 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 3115225 + 40551424 = 1765^2 + 6368^2 .

It is a cyclic number.

It is not a de Polignac number, because 43666649 - 2¹⁶ = 43601113 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (43666639) 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, 1679474 + ... + 1679499.

It is an arithmetic number, because the mean of its divisors is an integer number (11756409).

Almost surely, 2^43666649 is an apocalyptic number.

It is an amenable number.

43666649 is a deficient number, since it is larger than the sum of its proper divisors (3358987).

43666649 is a wasteful number, since it uses less digits than its factorization.

43666649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3358986.

The product of its digits is 559872, while the sum is 44.

The square root of 43666649 is about 6608.0745304514. The cubic root of 43666649 is about 352.1410231469.

The spelling of 43666649 in words is "forty-three million, six hundred sixty-six thousand, six hundred forty-nine".