5666609921 has 4 divisors (see below), whose sum is σ = 6476125632. Its totient is φ = 4857094212.

The previous prime is 5666609917. The next prime is 5666609929. The reversal of 5666609921 is 1299066665.

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 5666609921 - 2² = 5666609917 is a prime.

It is a super-2 number, since 2×5666609921² = 64220935993551252482, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 5666609921.

It is not an unprimeable number, because it can be changed into a prime (5666609929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 404757845 + ... + 404757858.

It is an arithmetic number, because the mean of its divisors is an integer number (1619031408).

Almost surely, 2^5666609921 is an apocalyptic number.

It is an amenable number.

5666609921 is a deficient number, since it is larger than the sum of its proper divisors (809515711).

5666609921 is an equidigital number, since it uses as much as digits as its factorization.

5666609921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 809515710.

The product of its (nonzero) digits is 1049760, while the sum is 50.

The square root of 5666609921 is about 75276.8883589113. Note that the first 3 decimals coincide. The cubic root of 5666609921 is about 1782.8211293514.

The spelling of 5666609921 in words is "five billion, six hundred sixty-six million, six hundred nine thousand, nine hundred twenty-one".