56521805909 has 2 divisors, whose sum is σ = 56521805910. Its totient is φ = 56521805908.

The previous prime is 56521805869. The next prime is 56521805917. The reversal of 56521805909 is 90950812565.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47171496100 + 9350309809 = 217190^2 + 96697^2 .

It is a cyclic number.

It is not a de Polignac number, because 56521805909 - 2²⁰ = 56520757333 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (56521804909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28260902954 + 28260902955.

It is an arithmetic number, because the mean of its divisors is an integer number (28260902955).

Almost surely, 2^56521805909 is an apocalyptic number.

It is an amenable number.

56521805909 is a deficient number, since it is larger than the sum of its proper divisors (1).

56521805909 is an equidigital number, since it uses as much as digits as its factorization.

56521805909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 972000, while the sum is 50.

The spelling of 56521805909 in words is "fifty-six billion, five hundred twenty-one million, eight hundred five thousand, nine hundred nine".