1667665 has 4 divisors (see below), whose sum is σ = 2001204. Its totient is φ = 1334128.

The previous prime is 1667663. The next prime is 1667689. The reversal of 1667665 is 5667661.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5667661 = 53 ⋅106937.

It can be written as a sum of positive squares in 2 ways, for example, as 982081 + 685584 = 991^2 + 828^2 .

It is a cyclic number.

It is not a de Polignac number, because 1667665 - 2¹ = 1667663 is a prime.

It is a super-2 number, since 2×1667665² = 5562213104450, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1667663) 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, 166762 + ... + 166771.

It is an arithmetic number, because the mean of its divisors is an integer number (500301).

2^1667665 is an apocalyptic number.

It is an amenable number.

1667665 is a deficient number, since it is larger than the sum of its proper divisors (333539).

1667665 is an equidigital number, since it uses as much as digits as its factorization.

1667665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333538.

The product of its digits is 45360, while the sum is 37.

The square root of 1667665 is about 1291.3810436893. The cubic root of 1667665 is about 118.5867785255.

It can be divided in two parts, 1667 and 665, that added together give a palindrome (2332).

The spelling of 1667665 in words is "one million, six hundred sixty-seven thousand, six hundred sixty-five".