55566809 has 2 divisors, whose sum is σ = 55566810. Its totient is φ = 55566808.

The previous prime is 55566799. The next prime is 55566817. The reversal of 55566809 is 90866555.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55547209 + 19600 = 7453^2 + 140^2 .

It is a cyclic number.

It is not a de Polignac number, because 55566809 - 2¹² = 55562713 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 55566809.

It is not a weakly prime, because it can be changed into another prime (55566869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27783404 + 27783405.

It is an arithmetic number, because the mean of its divisors is an integer number (27783405).

Almost surely, 2^55566809 is an apocalyptic number.

It is an amenable number.

55566809 is a deficient number, since it is larger than the sum of its proper divisors (1).

55566809 is an equidigital number, since it uses as much as digits as its factorization.

55566809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324000, while the sum is 44.

The square root of 55566809 is about 7454.3147907772. The cubic root of 55566809 is about 381.5971764013.

The spelling of 55566809 in words is "fifty-five million, five hundred sixty-six thousand, eight hundred nine".