51499881216 has 864 divisors, whose sum is σ = 191259532800. Its totient is φ = 13586227200.

The previous prime is 51499881211. The next prime is 51499881229. The reversal of 51499881216 is 61218899415.

51499881216 is a `hidden beast` number, since 51 + 499 + 8 + 81 + 21 + 6 = 666.

51499881216 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (864).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (51499881211) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 341058741 + ... + 341058891.

It is an arithmetic number, because the mean of its divisors is an integer number (221365200).

Almost surely, 2^51499881216 is an apocalyptic number.

51499881216 is a gapful number since it is divisible by the number (56) 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 51499881216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95629766400).

51499881216 is an abundant number, since it is smaller than the sum of its proper divisors (139759651584).

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

51499881216 is a wasteful number, since it uses less digits than its factorization.

51499881216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 262 (or 235 counting only the distinct ones).

The product of its digits is 1244160, while the sum is 54.

The spelling of 51499881216 in words is "fifty-one billion, four hundred ninety-nine million, eight hundred eighty-one thousand, two hundred sixteen".