166561311 has 16 divisors (see below), whose sum is σ = 259999488. Its totient is φ = 92856000.

The previous prime is 166561301. The next prime is 166561313. The reversal of 166561311 is 113165661.

It is not a de Polignac number, because 166561311 - 2⁷ = 166561183 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166561313) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 95865 + ... + 97586.

It is an arithmetic number, because the mean of its divisors is an integer number (16249968).

Almost surely, 2^166561311 is an apocalyptic number.

166561311 is a deficient number, since it is larger than the sum of its proper divisors (93438177).

166561311 is a wasteful number, since it uses less digits than its factorization.

166561311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193502.

The product of its digits is 3240, while the sum is 30.

The square root of 166561311 is about 12905.8634348888. The cubic root of 166561311 is about 550.2052247911.

The spelling of 166561311 in words is "one hundred sixty-six million, five hundred sixty-one thousand, three hundred eleven".