166555553 has 2 divisors, whose sum is σ = 166555554. Its totient is φ = 166555552.

The previous prime is 166555549. The next prime is 166555573. The reversal of 166555553 is 355555661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 143592289 + 22963264 = 11983^2 + 4792^2 .

It is a cyclic number.

It is not a de Polignac number, because 166555553 - 2² = 166555549 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 166555553.

It is not a weakly prime, because it can be changed into another prime (166555513) 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 as a sum of consecutive naturals, namely, 83277776 + 83277777.

It is an arithmetic number, because the mean of its divisors is an integer number (83277777).

Almost surely, 2^166555553 is an apocalyptic number.

It is an amenable number.

166555553 is a deficient number, since it is larger than the sum of its proper divisors (1).

166555553 is an equidigital number, since it uses as much as digits as its factorization.

166555553 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 337500, while the sum is 41.

The square root of 166555553 is about 12905.6403560614. The cubic root of 166555553 is about 550.1988845469.

The spelling of 166555553 in words is "one hundred sixty-six million, five hundred fifty-five thousand, five hundred fifty-three".