165105661 has 12 divisors (see below), whose sum is σ = 197257312. Its totient is φ = 135363096.

The previous prime is 165105641. The next prime is 165105667. The reversal of 165105661 is 166501561.

It is not a de Polignac number, because 165105661 - 2⁷ = 165105533 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165105667) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18591 + ... + 25996.

Almost surely, 2^165105661 is an apocalyptic number.

It is an amenable number.

165105661 is a deficient number, since it is larger than the sum of its proper divisors (32151651).

165105661 is an equidigital number, since it uses as much as digits as its factorization.

165105661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44640 (or 44617 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 31.

The square root of 165105661 is about 12849.3447692869. The cubic root of 165105661 is about 548.5977070583.

The spelling of 165105661 in words is "one hundred sixty-five million, one hundred five thousand, six hundred sixty-one".