549981 has 12 divisors (see below), whose sum is σ = 810108. Its totient is φ = 359424.

The previous prime is 549979. The next prime is 550007. The reversal of 549981 is 189945.

It can be written as a sum of positive squares in 2 ways, for example, as 416025 + 133956 = 645^2 + 366^2 .

It is not a de Polignac number, because 549981 - 2¹ = 549979 is a prime.

It is a super-2 number, since 2×549981² = 604958200722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (549911) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 100 + ... + 1053.

It is an arithmetic number, because the mean of its divisors is an integer number (67509).

2⁵⁴⁹⁹⁸¹ is an apocalyptic number.

It is an amenable number.

549981 is a deficient number, since it is larger than the sum of its proper divisors (260127).

549981 is a wasteful number, since it uses less digits than its factorization.

549981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1212 (or 1209 counting only the distinct ones).

The product of its digits is 12960, while the sum is 36.

The square root of 549981 is about 741.6070388015. The cubic root of 549981 is about 81.9311835883.

Subtracting from 549981 its sum of digits (36), we obtain a palindrome (549945).

The spelling of 549981 in words is "five hundred forty-nine thousand, nine hundred eighty-one".