165999549 has 8 divisors (see below), whose sum is σ = 221617120. Its totient is φ = 110524176.

The previous prime is 165999539. The next prime is 165999553. The reversal of 165999549 is 945999561.

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

It is not a de Polignac number, because 165999549 - 2⁵ = 165999517 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165999539) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32794 + ... + 37515.

It is an arithmetic number, because the mean of its divisors is an integer number (27702140).

Almost surely, 2^165999549 is an apocalyptic number.

It is an amenable number.

165999549 is a deficient number, since it is larger than the sum of its proper divisors (55617571).

165999549 is an equidigital number, since it uses as much as digits as its factorization.

165999549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71099.

The product of its digits is 3936600, while the sum is 57.

The square root of 165999549 is about 12884.0812245189. The cubic root of 165999549 is about 549.5859682912.

The spelling of 165999549 in words is "one hundred sixty-five million, nine hundred ninety-nine thousand, five hundred forty-nine".