53781 has 16 divisors (see below), whose sum is σ = 88704. Its totient is φ = 28224.

The previous prime is 53777. The next prime is 53783. The reversal of 53781 is 18735.

It is not a de Polignac number, because 53781 - 2² = 53777 is a prime.

It is a super-2 number, since 2×53781² = 5784791922, which contains 22 as substring.

It is a Curzon number.

53781 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (53783) 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 15 ways as a sum of consecutive naturals, for example, 175 + ... + 371.

It is an arithmetic number, because the mean of its divisors is an integer number (5544).

2⁵³⁷⁸¹ is an apocalyptic number.

It is an amenable number.

53781 is a deficient number, since it is larger than the sum of its proper divisors (34923).

53781 is a wasteful number, since it uses less digits than its factorization.

53781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220.

The product of its digits is 840, while the sum is 24.

The square root of 53781 is about 231.9073090698. The cubic root of 53781 is about 37.7464654674.

The spelling of 53781 in words is "fifty-three thousand, seven hundred eighty-one".