165071521 has 8 divisors (see below), whose sum is σ = 170558784. Its totient is φ = 159672240.

The previous prime is 165071519. The next prime is 165071591. The reversal of 165071521 is 125170561.

165071521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 165071521 - 2¹ = 165071519 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 165071521.

It is not an unprimeable number, because it can be changed into a prime (165071591) 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, 18171 + ... + 25696.

It is an arithmetic number, because the mean of its divisors is an integer number (21319848).

Almost surely, 2^165071521 is an apocalyptic number.

It is an amenable number.

165071521 is a deficient number, since it is larger than the sum of its proper divisors (5487263).

165071521 is an equidigital number, since it uses as much as digits as its factorization.

165071521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43991.

The product of its (nonzero) digits is 2100, while the sum is 28.

The square root of 165071521 is about 12848.0162281965. The cubic root of 165071521 is about 548.5598920481.

The spelling of 165071521 in words is "one hundred sixty-five million, seventy-one thousand, five hundred twenty-one".