51598321920 has 540 divisors, whose sum is σ = 192463826940. Its totient is φ = 13183672320.

The previous prime is 51598321897. The next prime is 51598321921. The reversal of 51598321920 is 2912389515.

51598321920 is a `hidden beast` number, since 5 + 1 + 598 + 32 + 1 + 9 + 20 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 22774431744 + 28823890176 = 150912^2 + 169776^2 .

It is a tau number, because it is divible by the number of its divisors (540).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51598321921) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 393880255 + ... + 393880385.

Almost surely, 2^51598321920 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 51598321920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96231913470).

51598321920 is an abundant number, since it is smaller than the sum of its proper divisors (140865505020).

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

51598321920 is an equidigital number, since it uses as much as digits as its factorization.

51598321920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 324 (or 170 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 45.

The spelling of 51598321920 in words is "fifty-one billion, five hundred ninety-eight million, three hundred twenty-one thousand, nine hundred twenty".