545781 has 4 divisors (see below), whose sum is σ = 727712. Its totient is φ = 363852.

The previous prime is 545773. The next prime is 545789. The reversal of 545781 is 187545.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (545773) and next prime (545789).

It is not a de Polignac number, because 545781 - 2³ = 545773 is a prime.

It is a super-2 number, since 2×545781² = 595753799922, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (545789) 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 3 ways as a sum of consecutive naturals, for example, 90961 + ... + 90966.

It is an arithmetic number, because the mean of its divisors is an integer number (181928).

2⁵⁴⁵⁷⁸¹ is an apocalyptic number.

It is an amenable number.

545781 is a deficient number, since it is larger than the sum of its proper divisors (181931).

545781 is a wasteful number, since it uses less digits than its factorization.

545781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181930.

The product of its digits is 5600, while the sum is 30.

The square root of 545781 is about 738.7699235892. The cubic root of 545781 is about 81.7220911194.

It can be divided in two parts, 545 and 781, that added together give a triangular number (1326 = T₅₁).

The spelling of 545781 in words is "five hundred forty-five thousand, seven hundred eighty-one".