43673921 has 2 divisors, whose sum is σ = 43673922. Its totient is φ = 43673920.

The previous prime is 43673911. The next prime is 43673923. The reversal of 43673921 is 12937634.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41783296 + 1890625 = 6464^2 + 1375^2 .

It is a cyclic number.

It is not a de Polignac number, because 43673921 - 2¹⁸ = 43411777 is a prime.

It is a super-2 number, since 2×43673921² = 3814822751028482, which contains 22 as substring.

Together with 43673923, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (43673923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21836960 + 21836961.

It is an arithmetic number, because the mean of its divisors is an integer number (21836961).

Almost surely, 2^43673921 is an apocalyptic number.

It is an amenable number.

43673921 is a deficient number, since it is larger than the sum of its proper divisors (1).

43673921 is an equidigital number, since it uses as much as digits as its factorization.

43673921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27216, while the sum is 35.

The square root of 43673921 is about 6608.6247434697. The cubic root of 43673921 is about 352.1605699287.

The spelling of 43673921 in words is "forty-three million, six hundred seventy-three thousand, nine hundred twenty-one".