165159821 has 8 divisors (see below), whose sum is σ = 168725760. Its totient is φ = 161619552.

The previous prime is 165159793. The next prime is 165159829. The reversal of 165159821 is 128951561.

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

It is a cyclic number.

It is not a de Polignac number, because 165159821 - 2¹⁴ = 165143437 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 (165159829) 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, 6881 + ... + 19433.

It is an arithmetic number, because the mean of its divisors is an integer number (21090720).

Almost surely, 2^165159821 is an apocalyptic number.

It is an amenable number.

165159821 is a deficient number, since it is larger than the sum of its proper divisors (3565939).

165159821 is a wasteful number, since it uses less digits than its factorization.

165159821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12835.

The product of its digits is 21600, while the sum is 38.

The square root of 165159821 is about 12851.4520969422. The cubic root of 165159821 is about 548.6576864343.

The spelling of 165159821 in words is "one hundred sixty-five million, one hundred fifty-nine thousand, eight hundred twenty-one".