217638235841557 has 16 divisors (see below), whose sum is σ = 218348373888000. Its totient is φ = 216929180692224.

The previous prime is 217638235841549. The next prime is 217638235841591. The reversal of 217638235841557 is 755148532836712.

217638235841557 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 217638235841557 - 2³ = 217638235841549 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 217638235841492 and 217638235841501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217638235841527) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5563472244 + ... + 5563511362.

It is an arithmetic number, because the mean of its divisors is an integer number (13646773368000).

Almost surely, 2^{217638235841557} is an apocalyptic number.

It is an amenable number.

217638235841557 is a deficient number, since it is larger than the sum of its proper divisors (710138046443).

217638235841557 is a wasteful number, since it uses less digits than its factorization.

217638235841557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52500.

The product of its digits is 338688000, while the sum is 67.

The spelling of 217638235841557 in words is "two hundred seventeen trillion, six hundred thirty-eight billion, two hundred thirty-five million, eight hundred forty-one thousand, five hundred fifty-seven".