51601331565 has 96 divisors (see below), whose sum is σ = 112938748416. Its totient is φ = 21236244480.

The previous prime is 51601331557. The next prime is 51601331591. The reversal of 51601331565 is 56513310615.

51601331565 is a `hidden beast` number, since 5 + 1 + 60 + 1 + 3 + 31 + 565 = 666.

It is not a de Polignac number, because 51601331565 - 2³ = 51601331557 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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 95 ways as a sum of consecutive naturals, for example, 86316 + ... + 332645.

It is an arithmetic number, because the mean of its divisors is an integer number (1176445296).

Almost surely, 2^51601331565 is an apocalyptic number.

It is an amenable number.

51601331565 is an abundant number, since it is smaller than the sum of its proper divisors (61337416851).

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

51601331565 is a wasteful number, since it uses less digits than its factorization.

51601331565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419019 (or 419016 counting only the distinct ones).

The product of its (nonzero) digits is 40500, while the sum is 36.

The spelling of 51601331565 in words is "fifty-one billion, six hundred one million, three hundred thirty-one thousand, five hundred sixty-five".