51040 has 48 divisors (see below), whose sum is σ = 136080. Its totient is φ = 17920.

The previous prime is 51031. The next prime is 51043. The reversal of 51040 is 4015.

51040 is a nontrivial binomial coefficient, being equal to C(320, 2).

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a nialpdrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51043) 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 7 ways as a sum of consecutive naturals, for example, 1746 + ... + 1774.

It is an arithmetic number, because the mean of its divisors is an integer number (2835).

2⁵¹⁰⁴⁰ is an apocalyptic number.

51040 is the 319-th triangular number and also the 160-th hexagonal number.

51040 is the 107-th centered nonagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (68040).

51040 is an abundant number, since it is smaller than the sum of its proper divisors (85040).

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

51040 is a wasteful number, since it uses less digits than its factorization.

51040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55 (or 47 counting only the distinct ones).

The product of its (nonzero) digits is 20, while the sum is 10.

The square root of 51040 is about 225.9203399431. The cubic root of 51040 is about 37.0939904003.

51040 divided by its product of nonzero digits (20) gives a palindrome (2552).

Adding to 51040 its reverse (4015), we get a palindrome (55055).

The spelling of 51040 in words is "fifty-one thousand, forty".