43816561 has 2 divisors, whose sum is σ = 43816562. Its totient is φ = 43816560.

The previous prime is 43816537. The next prime is 43816567. The reversal of 43816561 is 16561834.

It is a happy number.

43816561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 38056561 + 5760000 = 6169^2 + 2400^2 .

It is a cyclic number.

It is not a de Polignac number, because 43816561 - 2⁷ = 43816433 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (43816567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21908280 + 21908281.

It is an arithmetic number, because the mean of its divisors is an integer number (21908281).

Almost surely, 2^43816561 is an apocalyptic number.

It is an amenable number.

43816561 is a deficient number, since it is larger than the sum of its proper divisors (1).

43816561 is an equidigital number, since it uses as much as digits as its factorization.

43816561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17280, while the sum is 34.

The square root of 43816561 is about 6619.4079040349. The cubic root of 43816561 is about 352.5435413914.

The spelling of 43816561 in words is "forty-three million, eight hundred sixteen thousand, five hundred sixty-one".