165645215 has 4 divisors (see below), whose sum is σ = 198774264. Its totient is φ = 132516168.

The previous prime is 165645209. The next prime is 165645247. The reversal of 165645215 is 512546561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 512546561 = 2473 ⋅207257.

It is a cyclic number.

It is not a de Polignac number, because 165645215 - 2⁴ = 165645199 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16564517 + ... + 16564526.

It is an arithmetic number, because the mean of its divisors is an integer number (49693566).

Almost surely, 2^165645215 is an apocalyptic number.

165645215 is a deficient number, since it is larger than the sum of its proper divisors (33129049).

165645215 is an equidigital number, since it uses as much as digits as its factorization.

165645215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33129048.

The product of its digits is 36000, while the sum is 35.

The square root of 165645215 is about 12870.3230340190. The cubic root of 165645215 is about 549.1946505262.

The spelling of 165645215 in words is "one hundred sixty-five million, six hundred forty-five thousand, two hundred fifteen".