5666621 has 2 divisors, whose sum is σ = 5666622. Its totient is φ = 5666620.

The previous prime is 5666599. The next prime is 5666623. The reversal of 5666621 is 1266665.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3667225 + 1999396 = 1915^2 + 1414^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-5666621 is a prime.

It is a super-2 number, since 2×5666621² = 64221187115282, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 5666623, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (5666623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2833310 + 2833311.

It is an arithmetic number, because the mean of its divisors is an integer number (2833311).

Almost surely, 2^5666621 is an apocalyptic number.

It is an amenable number.

5666621 is a deficient number, since it is larger than the sum of its proper divisors (1).

5666621 is an equidigital number, since it uses as much as digits as its factorization.

5666621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 32.

The square root of 5666621 is about 2380.4665509097. The cubic root of 5666621 is about 178.2822291237.

The spelling of 5666621 in words is "five million, six hundred sixty-six thousand, six hundred twenty-one".