20217571553 has 2 divisors, whose sum is σ = 20217571554. Its totient is φ = 20217571552.

The previous prime is 20217571529. The next prime is 20217571597. The reversal of 20217571553 is 35517571202.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10726330624 + 9491240929 = 103568^2 + 97423^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20217571553 is a prime.

It is not a weakly prime, because it can be changed into another prime (20217591553) 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, 10108785776 + 10108785777.

It is an arithmetic number, because the mean of its divisors is an integer number (10108785777).

Almost surely, 2^20217571553 is an apocalyptic number.

It is an amenable number.

20217571553 is a deficient number, since it is larger than the sum of its proper divisors (1).

20217571553 is an equidigital number, since it uses as much as digits as its factorization.

20217571553 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 73500, while the sum is 38.

The spelling of 20217571553 in words is "twenty billion, two hundred seventeen million, five hundred seventy-one thousand, five hundred fifty-three".