51510205520 has 20 divisors (see below), whose sum is σ = 119761228020. Its totient is φ = 20604082176.

The previous prime is 51510205471. The next prime is 51510205543. The reversal of 51510205520 is 2550201515.

It can be written as a sum of positive squares in 2 ways, for example, as 26009948176 + 25500257344 = 161276^2 + 159688^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a self number, because there is not a number n which added to its sum of digits gives 51510205520.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 321938705 + ... + 321938864.

It is an arithmetic number, because the mean of its divisors is an integer number (5988061401).

Almost surely, 2^51510205520 is an apocalyptic number.

It is an amenable number.

51510205520 is an abundant number, since it is smaller than the sum of its proper divisors (68251022500).

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

51510205520 is a wasteful number, since it uses less digits than its factorization.

51510205520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 643877582 (or 643877576 counting only the distinct ones).

The product of its (nonzero) digits is 2500, while the sum is 26.

The spelling of 51510205520 in words is "fifty-one billion, five hundred ten million, two hundred five thousand, five hundred twenty".