20555111100557 has 4 divisors (see below), whose sum is σ = 22423757564256. Its totient is φ = 18686464636860.

The previous prime is 20555111100499. The next prime is 20555111100611. The reversal of 20555111100557 is 75500111155502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20555111100557 - 2⁸ = 20555111100301 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20555111100557.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20555111100157) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 934323231833 + ... + 934323231854.

It is an arithmetic number, because the mean of its divisors is an integer number (5605939391064).

Almost surely, 2^{20555111100557} is an apocalyptic number.

It is an amenable number.

20555111100557 is a deficient number, since it is larger than the sum of its proper divisors (1868646463699).

20555111100557 is a wasteful number, since it uses less digits than its factorization.

20555111100557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1868646463698.

The product of its (nonzero) digits is 43750, while the sum is 38.

Subtracting 20555111100557 from its reverse (75500111155502), we obtain a palindrome (54945000054945).

The spelling of 20555111100557 in words is "twenty trillion, five hundred fifty-five billion, one hundred eleven million, one hundred thousand, five hundred fifty-seven".