43917872561 has 2 divisors, whose sum is σ = 43917872562. Its totient is φ = 43917872560.

The previous prime is 43917872473. The next prime is 43917872597. The reversal of 43917872561 is 16527871934.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29281712161 + 14636160400 = 171119^2 + 120980^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-43917872561 is a prime.

It is not a weakly prime, because it can be changed into another prime (43917877561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21958936280 + 21958936281.

It is an arithmetic number, because the mean of its divisors is an integer number (21958936281).

Almost surely, 2^43917872561 is an apocalyptic number.

It is an amenable number.

43917872561 is a deficient number, since it is larger than the sum of its proper divisors (1).

43917872561 is an equidigital number, since it uses as much as digits as its factorization.

43917872561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2540160, while the sum is 53.

The spelling of 43917872561 in words is "forty-three billion, nine hundred seventeen million, eight hundred seventy-two thousand, five hundred sixty-one".