165642261 has 8 divisors (see below), whose sum is σ = 223338240. Its totient is φ = 109187232.

The previous prime is 165642233. The next prime is 165642299. The reversal of 165642261 is 162246561.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 165642261 - 2¹⁰ = 165641237 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165642221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 309925 + ... + 310458.

It is an arithmetic number, because the mean of its divisors is an integer number (27917280).

Almost surely, 2^165642261 is an apocalyptic number.

It is an amenable number.

165642261 is a deficient number, since it is larger than the sum of its proper divisors (57695979).

165642261 is an equidigital number, since it uses as much as digits as its factorization.

165642261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 620475.

The product of its digits is 17280, while the sum is 33.

The square root of 165642261 is about 12870.2082733730. The cubic root of 165642261 is about 549.1913858567.

The spelling of 165642261 in words is "one hundred sixty-five million, six hundred forty-two thousand, two hundred sixty-one".