51699356820 has 288 divisors, whose sum is σ = 168537358080. Its totient is φ = 12789964800.

The previous prime is 51699356803. The next prime is 51699356827. The reversal of 51699356820 is 2865399615.

It is a happy number.

51699356820 is a `hidden beast` number, since 51 + 6 + 9 + 9 + 3 + 568 + 20 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51699356827) by changing a digit.

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 95 ways as a sum of consecutive naturals, for example, 33504969 + ... + 33506511.

It is an arithmetic number, because the mean of its divisors is an integer number (585199160).

Almost surely, 2^51699356820 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 51699356820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84268679040).

51699356820 is an abundant number, since it is smaller than the sum of its proper divisors (116838001260).

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

51699356820 is a wasteful number, since it uses less digits than its factorization.

51699356820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1775 (or 1770 counting only the distinct ones).

The product of its (nonzero) digits is 3499200, while the sum is 54.

The spelling of 51699356820 in words is "fifty-one billion, six hundred ninety-nine million, three hundred fifty-six thousand, eight hundred twenty".