165890645 has 4 divisors (see below), whose sum is σ = 199068780. Its totient is φ = 132712512.

The previous prime is 165890639. The next prime is 165890677. The reversal of 165890645 is 546098561.

165890645 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 546098561 = 10903 ⋅50087.

It can be written as a sum of positive squares in 2 ways, for example, as 132181009 + 33709636 = 11497^2 + 5806^2 .

It is a cyclic number.

It is not a de Polignac number, because 165890645 - 2²⁴ = 149113429 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 165890596 and 165890605.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16589060 + ... + 16589069.

It is an arithmetic number, because the mean of its divisors is an integer number (49767195).

Almost surely, 2^165890645 is an apocalyptic number.

It is an amenable number.

165890645 is a deficient number, since it is larger than the sum of its proper divisors (33178135).

165890645 is an equidigital number, since it uses as much as digits as its factorization.

165890645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33178134.

The product of its (nonzero) digits is 259200, while the sum is 44.

The square root of 165890645 is about 12879.8542305416. The cubic root of 165890645 is about 549.4657567121.

The spelling of 165890645 in words is "one hundred sixty-five million, eight hundred ninety thousand, six hundred forty-five".