550666561 has 4 divisors (see below), whose sum is σ = 553549824. Its totient is φ = 547783300.

The previous prime is 550666559. The next prime is 550666637. The reversal of 550666561 is 165666055.

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 a cyclic number.

It is not a de Polignac number, because 550666561 - 2¹ = 550666559 is a prime.

It is a super-2 number, since 2×550666561² = 606467322807133442, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (550666511) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1441345 + ... + 1441726.

It is an arithmetic number, because the mean of its divisors is an integer number (138387456).

Almost surely, 2^550666561 is an apocalyptic number.

It is an amenable number.

550666561 is a deficient number, since it is larger than the sum of its proper divisors (2883263).

550666561 is a wasteful number, since it uses less digits than its factorization.

550666561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2883262.

The product of its (nonzero) digits is 162000, while the sum is 40.

The square root of 550666561 is about 23466.2856242738. The cubic root of 550666561 is about 819.6521234075.

The spelling of 550666561 in words is "five hundred fifty million, six hundred sixty-six thousand, five hundred sixty-one".