20565600257 has 2 divisors, whose sum is σ = 20565600258. Its totient is φ = 20565600256.

The previous prime is 20565600217. The next prime is 20565600359. The reversal of 20565600257 is 75200656502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20414408641 + 151191616 = 142879^2 + 12296^2 .

It is a cyclic number.

It is not a de Polignac number, because 20565600257 - 2⁶ = 20565600193 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20565600257.

It is not a weakly prime, because it can be changed into another prime (20565600217) 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, 10282800128 + 10282800129.

It is an arithmetic number, because the mean of its divisors is an integer number (10282800129).

Almost surely, 2^20565600257 is an apocalyptic number.

It is an amenable number.

20565600257 is a deficient number, since it is larger than the sum of its proper divisors (1).

20565600257 is an equidigital number, since it uses as much as digits as its factorization.

20565600257 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 126000, while the sum is 38.

The spelling of 20565600257 in words is "twenty billion, five hundred sixty-five million, six hundred thousand, two hundred fifty-seven".