43421909 has 2 divisors, whose sum is σ = 43421910. Its totient is φ = 43421908.

The previous prime is 43421881. The next prime is 43421923. The reversal of 43421909 is 90912434.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28622500 + 14799409 = 5350^2 + 3847^2 .

It is a cyclic number.

It is not a de Polignac number, because 43421909 - 2²⁴ = 26644693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43421969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21710954 + 21710955.

It is an arithmetic number, because the mean of its divisors is an integer number (21710955).

Almost surely, 2^43421909 is an apocalyptic number.

It is an amenable number.

43421909 is a deficient number, since it is larger than the sum of its proper divisors (1).

43421909 is an equidigital number, since it uses as much as digits as its factorization.

43421909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 43421909 is about 6589.5302563992. The cubic root of 43421909 is about 351.4819044971.

The spelling of 43421909 in words is "forty-three million, four hundred twenty-one thousand, nine hundred nine".