166555405 has 16 divisors (see below), whose sum is σ = 207097344. Its totient is φ = 128456640.

The previous prime is 166555393. The next prime is 166555457. The reversal of 166555405 is 504555661.

It is not a de Polignac number, because 166555405 - 2¹⁵ = 166522637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 in 15 ways as a sum of consecutive naturals, for example, 41967 + ... + 45763.

It is an arithmetic number, because the mean of its divisors is an integer number (12943584).

Almost surely, 2^166555405 is an apocalyptic number.

It is an amenable number.

166555405 is a deficient number, since it is larger than the sum of its proper divisors (40541939).

166555405 is a wasteful number, since it uses less digits than its factorization.

166555405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4116.

The product of its (nonzero) digits is 90000, while the sum is 37.

The square root of 166555405 is about 12905.6346221331. The cubic root of 166555405 is about 550.1987215793.

The spelling of 166555405 in words is "one hundred sixty-six million, five hundred fifty-five thousand, four hundred five".