43135921 has 2 divisors, whose sum is σ = 43135922. Its totient is φ = 43135920.

The previous prime is 43135901. The next prime is 43136039. The reversal of 43135921 is 12953134.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40449600 + 2686321 = 6360^2 + 1639^2 .

It is a cyclic number.

It is not a de Polignac number, because 43135921 - 2⁷ = 43135793 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 43135921.

It is not a weakly prime, because it can be changed into another prime (43135901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21567960 + 21567961.

It is an arithmetic number, because the mean of its divisors is an integer number (21567961).

Almost surely, 2^43135921 is an apocalyptic number.

It is an amenable number.

43135921 is a deficient number, since it is larger than the sum of its proper divisors (1).

43135921 is an equidigital number, since it uses as much as digits as its factorization.

43135921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3240, while the sum is 28.

The square root of 43135921 is about 6567.7942263746. The cubic root of 43135921 is about 350.7085537237.

The spelling of 43135921 in words is "forty-three million, one hundred thirty-five thousand, nine hundred twenty-one".