43898809 has 2 divisors, whose sum is σ = 43898810. Its totient is φ = 43898808.

The previous prime is 43898807. The next prime is 43898863. The reversal of 43898809 is 90889834.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30415225 + 13483584 = 5515^2 + 3672^2 .

It is a cyclic number.

It is not a de Polignac number, because 43898809 - 2¹ = 43898807 is a prime.

Together with 43898807, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (43898807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21949404 + 21949405.

It is an arithmetic number, because the mean of its divisors is an integer number (21949405).

Almost surely, 2^43898809 is an apocalyptic number.

It is an amenable number.

43898809 is a deficient number, since it is larger than the sum of its proper divisors (1).

43898809 is an equidigital number, since it uses as much as digits as its factorization.

43898809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 497664, while the sum is 49.

The square root of 43898809 is about 6625.6176315873. The cubic root of 43898809 is about 352.7639898295.

Subtracting 43898809 from its reverse (90889834), we obtain a square (46991025 = 6855²).

The spelling of 43898809 in words is "forty-three million, eight hundred ninety-eight thousand, eight hundred nine".