43400909 has 4 divisors (see below), whose sum is σ = 43995516. Its totient is φ = 42806304.

The previous prime is 43400891. The next prime is 43400911. The reversal of 43400909 is 90900434.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90900434 = 2 ⋅45450217.

It can be written as a sum of positive squares in 2 ways, for example, as 14478025 + 28922884 = 3805^2 + 5378^2 .

It is a cyclic number.

It is not a de Polignac number, because 43400909 - 2⁸ = 43400653 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 (43400969) 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, 297194 + ... + 297339.

It is an arithmetic number, because the mean of its divisors is an integer number (10998879).

Almost surely, 2^43400909 is an apocalyptic number.

It is an amenable number.

43400909 is a deficient number, since it is larger than the sum of its proper divisors (594607).

43400909 is an equidigital number, since it uses as much as digits as its factorization.

43400909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 594606.

The product of its (nonzero) digits is 3888, while the sum is 29.

The square root of 43400909 is about 6587.9366268962. The cubic root of 43400909 is about 351.4252333344.

The spelling of 43400909 in words is "forty-three million, four hundred thousand, nine hundred nine".