51280 has 20 divisors (see below), whose sum is σ = 119412. Its totient is φ = 20480.

The previous prime is 51263. The next prime is 51283. The reversal of 51280 is 8215.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 33856 + 17424 = 184^2 + 132^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a plaindrome in base 11.

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 (51283) by changing a digit.

51280 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 241 + ... + 400.

2⁵¹²⁸⁰ is an apocalyptic number.

It is an amenable number.

51280 is an abundant number, since it is smaller than the sum of its proper divisors (68132).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (59706).

51280 is a wasteful number, since it uses less digits than its factorization.

51280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 654 (or 648 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 51280 is about 226.4508776755. The cubic root of 51280 is about 37.1520405582.

Adding to 51280 its product of nonzero digits (80), we get a triangular number (51360 = T₃₂₀).

Adding to 51280 its reverse (8215), we get a palindrome (59495).

It can be divided in two parts, 5 and 1280, that multiplied together give a square (6400 = 80²).

The spelling of 51280 in words is "fifty-one thousand, two hundred eighty".