51687633816 has 672 divisors, whose sum is σ = 190539279840. Its totient is φ = 12791955456.

The previous prime is 51687633773. The next prime is 51687633883. The reversal of 51687633816 is 61833678615.

51687633816 is a `hidden beast` number, since 516 + 87 + 6 + 3 + 38 + 16 = 666.

It is a super-3 number, since 3×51687633816³ (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 (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 167 ways as a sum of consecutive naturals, for example, 153375600 + ... + 153375936.

It is an arithmetic number, because the mean of its divisors is an integer number (283540595).

Almost surely, 2^51687633816 is an apocalyptic number.

51687633816 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 51687633816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95269639920).

51687633816 is an abundant number, since it is smaller than the sum of its proper divisors (138851646024).

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

51687633816 is a wasteful number, since it uses less digits than its factorization.

51687633816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 415 (or 379 counting only the distinct ones).

The product of its digits is 4354560, while the sum is 54.

The spelling of 51687633816 in words is "fifty-one billion, six hundred eighty-seven million, six hundred thirty-three thousand, eight hundred sixteen".