20635645557 has 8 divisors (see below), whose sum is σ = 27534326976. Its totient is φ = 13747030592.

The previous prime is 20635645549. The next prime is 20635645567. The reversal of 20635645557 is 75554653602.

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

It is a cyclic number.

It is not a de Polignac number, because 20635645557 - 2³ = 20635645549 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20635645567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2511828 + ... + 2520029.

It is an arithmetic number, because the mean of its divisors is an integer number (3441790872).

Almost surely, 2^20635645557 is an apocalyptic number.

It is an amenable number.

20635645557 is a deficient number, since it is larger than the sum of its proper divisors (6898681419).

20635645557 is a wasteful number, since it uses less digits than its factorization.

20635645557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5033227.

The product of its (nonzero) digits is 3780000, while the sum is 48.

The spelling of 20635645557 in words is "twenty billion, six hundred thirty-five million, six hundred forty-five thousand, five hundred fifty-seven".