20013171767557 has 2 divisors, whose sum is σ = 20013171767558. Its totient is φ = 20013171767556.

The previous prime is 20013171767507. The next prime is 20013171767647. The reversal of 20013171767557 is 75576717131002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11698766759716 + 8314405007841 = 3420346^2 + 2883471^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20013171767557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20013171767507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10006585883778 + 10006585883779.

It is an arithmetic number, because the mean of its divisors is an integer number (10006585883779).

Almost surely, 2^{20013171767557} is an apocalyptic number.

It is an amenable number.

20013171767557 is a deficient number, since it is larger than the sum of its proper divisors (1).

20013171767557 is an equidigital number, since it uses as much as digits as its factorization.

20013171767557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2160900, while the sum is 52.

Adding to 20013171767557 its reverse (75576717131002), we get a palindrome (95589888898559).

The spelling of 20013171767557 in words is "twenty trillion, thirteen billion, one hundred seventy-one million, seven hundred sixty-seven thousand, five hundred fifty-seven".