20503117357 has 2 divisors, whose sum is σ = 20503117358. Its totient is φ = 20503117356.

The previous prime is 20503117351. The next prime is 20503117391. The reversal of 20503117357 is 75371130502.

It is an a-pointer prime, because the next prime (20503117391) can be obtained adding 20503117357 to its sum of digits (34).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17338042276 + 3165075081 = 131674^2 + 56259^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20503117357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20503117351) 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, 10251558678 + 10251558679.

It is an arithmetic number, because the mean of its divisors is an integer number (10251558679).

Almost surely, 2^20503117357 is an apocalyptic number.

It is an amenable number.

20503117357 is a deficient number, since it is larger than the sum of its proper divisors (1).

20503117357 is an equidigital number, since it uses as much as digits as its factorization.

20503117357 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 22050, while the sum is 34.

Adding to 20503117357 its reverse (75371130502), we get a palindrome (95874247859).

The spelling of 20503117357 in words is "twenty billion, five hundred three million, one hundred seventeen thousand, three hundred fifty-seven".