51187840 has 96 divisors (see below), whose sum is σ = 134710380. Its totient is φ = 18585600.

The previous prime is 51187823. The next prime is 51187847. The reversal of 51187840 is 4878115.

It can be written as a sum of positive squares in 2 ways, for example, as 50808384 + 379456 = 7128^2 + 616^2 .

It is a junction number, because it is equal to n+sod(n) for n = 51187796 and 51187805.

It is not an unprimeable number, because it can be changed into a prime (51187847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 77110 + ... + 77770.

Almost surely, 2^51187840 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 51187840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67355190).

51187840 is an abundant number, since it is smaller than the sum of its proper divisors (83522540).

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

51187840 is a wasteful number, since it uses less digits than its factorization.

51187840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 702 (or 679 counting only the distinct ones).

The product of its (nonzero) digits is 8960, while the sum is 34.

The square root of 51187840 is about 7154.5677717106. The cubic root of 51187840 is about 371.2977076322.

The spelling of 51187840 in words is "fifty-one million, one hundred eighty-seven thousand, eight hundred forty".