20563936557 has 8 divisors (see below), whose sum is σ = 27419784480. Its totient is φ = 13708689840.

The previous prime is 20563936513. The next prime is 20563936567. The reversal of 20563936557 is 75563936502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20563936557 - 2⁷ = 20563936429 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20563936567) 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 in 7 ways as a sum of consecutive naturals, for example, 63294 + ... + 212447.

It is an arithmetic number, because the mean of its divisors is an integer number (3427473060).

Almost surely, 2^20563936557 is an apocalyptic number.

It is an amenable number.

20563936557 is a deficient number, since it is larger than the sum of its proper divisors (6855847923).

20563936557 is a wasteful number, since it uses less digits than its factorization.

20563936557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 300603.

The product of its (nonzero) digits is 5103000, while the sum is 51.

Subtracting 20563936557 from its reverse (75563936502), we obtain a palindrome (54999999945).

The spelling of 20563936557 in words is "twenty billion, five hundred sixty-three million, nine hundred thirty-six thousand, five hundred fifty-seven".