20517898757 has 8 divisors (see below), whose sum is σ = 21734116992. Its totient is φ = 19302712000.

The previous prime is 20517898729. The next prime is 20517898759. The reversal of 20517898757 is 75789871502.

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 20517898757 - 2²⁰ = 20516850181 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20517898696 and 20517898705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20517898759) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 216719 + ... + 296652.

It is an arithmetic number, because the mean of its divisors is an integer number (2716764624).

Almost surely, 2^20517898757 is an apocalyptic number.

It is an amenable number.

20517898757 is a deficient number, since it is larger than the sum of its proper divisors (1216218235).

20517898757 is a wasteful number, since it uses less digits than its factorization.

20517898757 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515739.

The product of its (nonzero) digits is 9878400, while the sum is 59.

The spelling of 20517898757 in words is "twenty billion, five hundred seventeen million, eight hundred ninety-eight thousand, seven hundred fifty-seven".