51516139968 has 168 divisors, whose sum is σ = 154238797440. Its totient is φ = 17047791360.

The previous prime is 51516139963. The next prime is 51516140021. The reversal of 51516139968 is 86993161515.

51516139968 is a `hidden beast` number, since 5 + 1 + 516 + 1 + 39 + 96 + 8 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51516139963) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2149813 + ... + 2173643.

It is an arithmetic number, because the mean of its divisors is an integer number (918088080).

Almost surely, 2^51516139968 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 51516139968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (77119398720).

51516139968 is an abundant number, since it is smaller than the sum of its proper divisors (102722657472).

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

51516139968 is a wasteful number, since it uses less digits than its factorization.

51516139968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23997 (or 23975 counting only the distinct ones).

The product of its digits is 1749600, while the sum is 54.

The spelling of 51516139968 in words is "fifty-one billion, five hundred sixteen million, one hundred thirty-nine thousand, nine hundred sixty-eight".