51805578240 has 528 divisors, whose sum is σ = 200535386688. Its totient is φ = 12748161024.

The previous prime is 51805578193. The next prime is 51805578247. The reversal of 51805578240 is 4287550815.

51805578240 is a `hidden beast` number, since 5 + 18 + 0 + 557 + 82 + 4 + 0 = 666.

It is a super-3 number, since 3×51805578240³ (a number of 33 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (51805578247) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 16172479 + ... + 16175681.

Almost surely, 2^51805578240 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 51805578240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100267693344).

51805578240 is an abundant number, since it is smaller than the sum of its proper divisors (148729808448).

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

51805578240 is a wasteful number, since it uses less digits than its factorization.

51805578240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3256 (or 3226 counting only the distinct ones).

The product of its (nonzero) digits is 448000, while the sum is 45.

The spelling of 51805578240 in words is "fifty-one billion, eight hundred five million, five hundred seventy-eight thousand, two hundred forty".