549661 has 16 divisors (see below), whose sum is σ = 691200. Its totient is φ = 426240.

The previous prime is 549649. The next prime is 549667. The reversal of 549661 is 166945.

It is a cyclic number.

It is not a de Polignac number, because 549661 - 2⁷ = 549533 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (549667) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3615 + ... + 3763.

It is an arithmetic number, because the mean of its divisors is an integer number (43200).

2⁵⁴⁹⁶⁶¹ is an apocalyptic number.

It is an amenable number.

549661 is a deficient number, since it is larger than the sum of its proper divisors (141539).

549661 is a wasteful number, since it uses less digits than its factorization.

549661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204.

The product of its digits is 6480, while the sum is 31.

The square root of 549661 is about 741.3912597273. The cubic root of 549661 is about 81.9152902725.

The spelling of 549661 in words is "five hundred forty-nine thousand, six hundred sixty-one".