45581 has 4 divisors (see below), whose sum is σ = 48000. Its totient is φ = 43164.

The previous prime is 45569. The next prime is 45587. The reversal of 45581 is 18554.

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, and also an emirpimes, since its reverse is a distinct semiprime: 18554 = 2 ⋅9277.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-45581 is a prime.

It is a super-2 number, since 2×45581² = 4155255122, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (45587) 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 3 ways as a sum of consecutive naturals, for example, 1181 + ... + 1218.

It is an arithmetic number, because the mean of its divisors is an integer number (12000).

2⁴⁵⁵⁸¹ is an apocalyptic number.

It is an amenable number.

45581 is a deficient number, since it is larger than the sum of its proper divisors (2419).

45581 is a wasteful number, since it uses less digits than its factorization.

45581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2418.

The product of its digits is 800, while the sum is 23.

The square root of 45581 is about 213.4970725795. The cubic root of 45581 is about 35.7213570760.

It can be divided in two parts, 45 and 581, that added together give a palindrome (626).

The spelling of 45581 in words is "forty-five thousand, five hundred eighty-one".