1865665 has 16 divisors (see below), whose sum is σ = 2426112. Its totient is φ = 1371904.

The previous prime is 1865659. The next prime is 1865671. The reversal of 1865665 is 5665681.

1865665 is nontrivially palindromic in base 16.

It is an interprime number because it is at equal distance from previous prime (1865659) and next prime (1865671).

It is a cyclic number.

It is not a de Polignac number, because 1865665 - 2⁷ = 1865537 is a prime.

It is a Duffinian number.

1865665 is a lucky number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3762 + ... + 4228.

It is an arithmetic number, because the mean of its divisors is an integer number (151632).

2^1865665 is an apocalyptic number.

It is an amenable number.

1865665 is a deficient number, since it is larger than the sum of its proper divisors (560447).

1865665 is a wasteful number, since it uses less digits than its factorization.

1865665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 536.

The product of its digits is 43200, while the sum is 37.

The square root of 1865665 is about 1365.8934804735. The cubic root of 1865665 is about 123.1056223638.

It can be divided in two parts, 18656 and 65, that added together give a triangular number (18721 = T₁₉₃).

The spelling of 1865665 in words is "one million, eight hundred sixty-five thousand, six hundred sixty-five".