1643165 has 4 divisors (see below), whose sum is σ = 1971804. Its totient is φ = 1314528.

The previous prime is 1643141. The next prime is 1643171. The reversal of 1643165 is 5613461.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1036324 + 606841 = 1018^2 + 779^2 .

It is a cyclic number.

It is not a de Polignac number, because 1643165 - 2⁸ = 1642909 is a prime.

It is a Duffinian number.

It is a Curzon number.

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, 164312 + ... + 164321.

It is an arithmetic number, because the mean of its divisors is an integer number (492951).

2^1643165 is an apocalyptic number.

It is an amenable number.

1643165 is a deficient number, since it is larger than the sum of its proper divisors (328639).

1643165 is an equidigital number, since it uses as much as digits as its factorization.

1643165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 328638.

The product of its digits is 2160, while the sum is 26.

The square root of 1643165 is about 1281.8599767525. The cubic root of 1643165 is about 118.0031838651.

The spelling of 1643165 in words is "one million, six hundred forty-three thousand, one hundred sixty-five".