43121246355661 has 2 divisors, whose sum is σ = 43121246355662. Its totient is φ = 43121246355660.

The previous prime is 43121246355647. The next prime is 43121246355773. The reversal of 43121246355661 is 16655364212134.

It is a happy number.

43121246355661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 37167617075625 + 5953629280036 = 6096525^2 + 2440006^2 .

It is a cyclic number.

It is not a de Polignac number, because 43121246355661 - 2¹¹ = 43121246353613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43121246355611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21560623177830 + 21560623177831.

It is an arithmetic number, because the mean of its divisors is an integer number (21560623177831).

Almost surely, 2^{43121246355661} is an apocalyptic number.

It is an amenable number.

43121246355661 is a deficient number, since it is larger than the sum of its proper divisors (1).

43121246355661 is an equidigital number, since it uses as much as digits as its factorization.

43121246355661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3110400, while the sum is 49.

The spelling of 43121246355661 in words is "forty-three trillion, one hundred twenty-one billion, two hundred forty-six million, three hundred fifty-five thousand, six hundred sixty-one".