165991966 has 32 divisors (see below), whose sum is σ = 298579968. Its totient is φ = 67668480.

The previous prime is 165991933. The next prime is 165991981. The reversal of 165991966 is 669199561.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60811 + ... + 63481.

It is an arithmetic number, because the mean of its divisors is an integer number (9330624).

Almost surely, 2^165991966 is an apocalyptic number.

165991966 is a deficient number, since it is larger than the sum of its proper divisors (132588002).

165991966 is a wasteful number, since it uses less digits than its factorization.

165991966 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2896.

The product of its digits is 787320, while the sum is 52.

The square root of 165991966 is about 12883.7869432865. The cubic root of 165991966 is about 549.5775996462.

The spelling of 165991966 in words is "one hundred sixty-five million, nine hundred ninety-one thousand, nine hundred sixty-six".