549408661 has 4 divisors (see below), whose sum is σ = 552255532. Its totient is φ = 546561792.

The previous prime is 549408637. The next prime is 549408701. The reversal of 549408661 is 166804945.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 120670225 + 428738436 = 10985^2 + 20706^2 .

It is a cyclic number.

It is not a de Polignac number, because 549408661 - 2⁹ = 549408149 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (549408631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1423146 + ... + 1423531.

It is an arithmetic number, because the mean of its divisors is an integer number (138063883).

Almost surely, 2^549408661 is an apocalyptic number.

It is an amenable number.

549408661 is a deficient number, since it is larger than the sum of its proper divisors (2846871).

549408661 is a wasteful number, since it uses less digits than its factorization.

549408661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2846870.

The product of its (nonzero) digits is 207360, while the sum is 43.

The square root of 549408661 is about 23439.4680187073. The cubic root of 549408661 is about 819.0275309873.

The spelling of 549408661 in words is "five hundred forty-nine million, four hundred eight thousand, six hundred sixty-one".