1641865 has 4 divisors (see below), whose sum is σ = 1970244. Its totient is φ = 1313488.

The previous prime is 1641863. The next prime is 1641881. The reversal of 1641865 is 5681461.

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 451584 + 1190281 = 672^2 + 1091^2 .

It is a cyclic number.

It is not a de Polignac number, because 1641865 - 2¹ = 1641863 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1641863) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 164182 + ... + 164191.

It is an arithmetic number, because the mean of its divisors is an integer number (492561).

2^1641865 is an apocalyptic number.

It is an amenable number.

1641865 is a deficient number, since it is larger than the sum of its proper divisors (328379).

1641865 is an equidigital number, since it uses as much as digits as its factorization.

1641865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328378.

The product of its digits is 5760, while the sum is 31.

The square root of 1641865 is about 1281.3528007540. The cubic root of 1641865 is about 117.9720560087.

The spelling of 1641865 in words is "one million, six hundred forty-one thousand, eight hundred sixty-five".