51809907520 has 112 divisors (see below), whose sum is σ = 141055636608. Its totient is φ = 17756006400.

The previous prime is 51809907491. The next prime is 51809907529. The reversal of 51809907520 is 2570990815.

It is a tau number, because it is divible by the number of its divisors (112).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51809907529) 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, 10415754 + ... + 10420726.

Almost surely, 2^51809907520 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51809907520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (70527818304).

51809907520 is an abundant number, since it is smaller than the sum of its proper divisors (89245729088).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51809907520 is a wasteful number, since it uses less digits than its factorization.

51809907520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9648 (or 9638 counting only the distinct ones).

The product of its (nonzero) digits is 226800, while the sum is 46.

The spelling of 51809907520 in words is "fifty-one billion, eight hundred nine million, nine hundred seven thousand, five hundred twenty".