166055561 has 40 divisors (see below), whose sum is σ = 210814464. Its totient is φ = 130394880.

The previous prime is 166055557. The next prime is 166055563. The reversal of 166055561 is 165550661.

It is not a de Polignac number, because 166055561 - 2² = 166055557 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (166055563) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1711865 + ... + 1711961.

Almost surely, 2^166055561 is an apocalyptic number.

It is an amenable number.

166055561 is a deficient number, since it is larger than the sum of its proper divisors (44758903).

166055561 is an frugal number, since it uses more digits than its factorization.

166055561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179 (or 158 counting only the distinct ones).

The product of its (nonzero) digits is 27000, while the sum is 35.

The square root of 166055561 is about 12886.2547313019. The cubic root of 166055561 is about 549.6477755827.

The spelling of 166055561 in words is "one hundred sixty-six million, fifty-five thousand, five hundred sixty-one".