51999856289640 has 1920 divisors, whose sum is σ = 217599788482560. Its totient is φ = 10902273242112.

The previous prime is 51999856289611. The next prime is 51999856289753. The reversal of 51999856289640 is 4698265899915.

51999856289640 is a `hidden beast` number, since 5 + 1 + 9 + 9 + 9 + 8 + 562 + 8 + 9 + 6 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a self number, because there is not a number n which added to its sum of digits gives 51999856289640.

It is an unprimeable number.

It is a polite number, since it can be written in 479 ways as a sum of consecutive naturals, for example, 44711827699 + ... + 44711828861.

It is an arithmetic number, because the mean of its divisors is an integer number (113333223168).

Almost surely, 2^{51999856289640} 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 51999856289640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108799894241280).

51999856289640 is an abundant number, since it is smaller than the sum of its proper divisors (165599932192920).

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

51999856289640 is a wasteful number, since it uses less digits than its factorization.

51999856289640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1401 (or 1369 counting only the distinct ones).

The product of its (nonzero) digits is 3023308800, while the sum is 81.

The spelling of 51999856289640 in words is "fifty-one trillion, nine hundred ninety-nine billion, eight hundred fifty-six million, two hundred eighty-nine thousand, six hundred forty".