43128691 has 4 divisors (see below), whose sum is σ = 43195392. Its totient is φ = 43061992.

The previous prime is 43128671. The next prime is 43128731. The reversal of 43128691 is 19682134.

43128691 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 an emirpimes, since its reverse is a distinct semiprime: 19682134 = 2 ⋅9841067.

It is a cyclic number.

It is not a de Polignac number, because 43128691 - 2⁹ = 43128179 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (43128661) 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, 32371 + ... + 33676.

It is an arithmetic number, because the mean of its divisors is an integer number (10798848).

Almost surely, 2^43128691 is an apocalyptic number.

43128691 is a deficient number, since it is larger than the sum of its proper divisors (66701).

43128691 is an equidigital number, since it uses as much as digits as its factorization.

43128691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66700.

The product of its digits is 10368, while the sum is 34.

The square root of 43128691 is about 6567.2437902061. The cubic root of 43128691 is about 350.6889585738.

The spelling of 43128691 in words is "forty-three million, one hundred twenty-eight thousand, six hundred ninety-one".