51780 has 24 divisors (see below), whose sum is σ = 145152. Its totient is φ = 13792.

The previous prime is 51769. The next prime is 51787. The reversal of 51780 is 8715.

It is a happy number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (51787) by changing a digit.

51780 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 372 + ... + 491.

It is an arithmetic number, because the mean of its divisors is an integer number (6048).

2⁵¹⁷⁸⁰ is an apocalyptic number.

It is an amenable number.

51780 is an abundant number, since it is smaller than the sum of its proper divisors (93372).

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 (72576).

51780 is a wasteful number, since it uses less digits than its factorization.

51780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 875 (or 873 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 21.

The square root of 51780 is about 227.5521918154. The cubic root of 51780 is about 37.2723991823.

The spelling of 51780 in words is "fifty-one thousand, seven hundred eighty".