51243520 has 80 divisors (see below), whose sum is σ = 126418248. Its totient is φ = 19906560.

The previous prime is 51243503. The next prime is 51243523. The reversal of 51243520 is 2534215.

It can be written as a sum of positive squares in 4 ways, for example, as 47114496 + 4129024 = 6864^2 + 2032^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 51243491 and 51243500.

It is not an unprimeable number, because it can be changed into a prime (51243523) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 94450 + ... + 94990.

Almost surely, 2^51243520 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 51243520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (63209124).

51243520 is an abundant number, since it is smaller than the sum of its proper divisors (75174728).

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

51243520 is an equidigital number, since it uses as much as digits as its factorization.

51243520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 601 (or 585 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 51243520 is about 7158.4579344996. The cubic root of 51243520 is about 371.4322862407.

Adding to 51243520 its reverse (2534215), we get a palindrome (53777735).

The spelling of 51243520 in words is "fifty-one million, two hundred forty-three thousand, five hundred twenty".