51820521984 has 640 divisors, whose sum is σ = 193744742400. Its totient is φ = 13284311040.

The previous prime is 51820521937. The next prime is 51820522007. The reversal of 51820521984 is 48912502815.

51820521984 is a `hidden beast` number, since 5 + 18 + 20 + 521 + 98 + 4 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 94735599 + ... + 94736145.

It is an arithmetic number, because the mean of its divisors is an integer number (302726160).

Almost surely, 2^51820521984 is an apocalyptic number.

51820521984 is a gapful number since it is divisible by the number (54) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51820521984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96872371200).

51820521984 is an abundant number, since it is smaller than the sum of its proper divisors (141924220416).

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

51820521984 is a wasteful number, since it uses less digits than its factorization.

51820521984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 681 (or 659 counting only the distinct ones).

The product of its (nonzero) digits is 230400, while the sum is 45.

It can be divided in two parts, 518 and 20521984, that added together give a palindrome (20522502).

The spelling of 51820521984 in words is "fifty-one billion, eight hundred twenty million, five hundred twenty-one thousand, nine hundred eighty-four".