51781774820 has 24 divisors (see below), whose sum is σ = 108781001784. Its totient is φ = 20705229056.

The previous prime is 51781774819. The next prime is 51781774829. The reversal of 51781774820 is 2847718715.

It can be written as a sum of positive squares in 4 ways, for example, as 9328469056 + 42453305764 = 96584^2 + 206042^2 .

It is not an unprimeable number, because it can be changed into a prime (51781774829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 410627 + ... + 521706.

It is an arithmetic number, because the mean of its divisors is an integer number (4532541741).

Almost surely, 2^51781774820 is an apocalyptic number.

It is an amenable number.

51781774820 is an abundant number, since it is smaller than the sum of its proper divisors (56999226964).

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

51781774820 is a wasteful number, since it uses less digits than its factorization.

51781774820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 935119 (or 935117 counting only the distinct ones).

The product of its (nonzero) digits is 878080, while the sum is 50.

The spelling of 51781774820 in words is "fifty-one billion, seven hundred eighty-one million, seven hundred seventy-four thousand, eight hundred twenty".