1644365 has 8 divisors (see below), whose sum is σ = 1985688. Its totient is φ = 1307200.

The previous prime is 1644361. The next prime is 1644367. The reversal of 1644365 is 5634461.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 158404 + 1485961 = 398^2 + 1219^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1644365 - 2² = 1644361 is a prime.

It is a super-3 number, since 3×1644365³ = 13338774411102981375, which contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1644361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 86 + ... + 1815.

It is an arithmetic number, because the mean of its divisors is an integer number (248211).

2^1644365 is an apocalyptic number.

It is an amenable number.

1644365 is a deficient number, since it is larger than the sum of its proper divisors (341323).

1644365 is a wasteful number, since it uses less digits than its factorization.

1644365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2079.

The product of its digits is 8640, while the sum is 29.

The square root of 1644365 is about 1282.3279611706. The cubic root of 1644365 is about 118.0319027021.

It can be divided in two parts, 1644 and 365, that multiplied together give a triangular number (600060 = T₁₀₉₅).

The spelling of 1644365 in words is "one million, six hundred forty-four thousand, three hundred sixty-five".