20555205217 has 2 divisors, whose sum is σ = 20555205218. Its totient is φ = 20555205216.

The previous prime is 20555205163. The next prime is 20555205221. The reversal of 20555205217 is 71250255502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12950667601 + 7604537616 = 113801^2 + 87204^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20555205217 is a prime.

It is not a weakly prime, because it can be changed into another prime (20555205287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10277602608 + 10277602609.

It is an arithmetic number, because the mean of its divisors is an integer number (10277602609).

Almost surely, 2^20555205217 is an apocalyptic number.

It is an amenable number.

20555205217 is a deficient number, since it is larger than the sum of its proper divisors (1).

20555205217 is an equidigital number, since it uses as much as digits as its factorization.

20555205217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 35000, while the sum is 34.

The spelling of 20555205217 in words is "twenty billion, five hundred fifty-five million, two hundred five thousand, two hundred seventeen".