56781 has 10 divisors (see below), whose sum is σ = 84942. Its totient is φ = 37800.

The previous prime is 56779. The next prime is 56783. The reversal of 56781 is 18765.

It is an interprime number because it is at equal distance from previous prime (56779) and next prime (56783).

It can be written as a sum of positive squares in only one way, i.e., 54756 + 2025 = 234^2 + 45^2 .

It is not a de Polignac number, because 56781 - 2¹ = 56779 is a prime.

It is a super-2 number, since 2×56781² = 6448163922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an alternating number because its digits alternate between odd and even.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 270 + ... + 431.

2⁵⁶⁷⁸¹ is an apocalyptic number.

It is an amenable number.

56781 is a deficient number, since it is larger than the sum of its proper divisors (28161).

56781 is an equidigital number, since it uses as much as digits as its factorization.

56781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 713 (or 704 counting only the distinct ones).

The product of its digits is 1680, while the sum is 27.

The square root of 56781 is about 238.2876413077. The cubic root of 56781 is about 38.4356602332.

It can be divided in two parts, 5 and 6781, that added together give a triangular number (6786 = T₁₁₆).

The spelling of 56781 in words is "fifty-six thousand, seven hundred eighty-one".