1671665 has 4 divisors (see below), whose sum is σ = 2006004. Its totient is φ = 1337328.

The previous prime is 1671643. The next prime is 1671671. The reversal of 1671665 is 5661761.

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 541696 + 1129969 = 736^2 + 1063^2 .

It is a cyclic number.

It is not a de Polignac number, because 1671665 - 2¹⁴ = 1655281 is a prime.

It is a Duffinian 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, 167162 + ... + 167171.

It is an arithmetic number, because the mean of its divisors is an integer number (501501).

2^1671665 is an apocalyptic number.

It is an amenable number.

1671665 is a deficient number, since it is larger than the sum of its proper divisors (334339).

1671665 is an equidigital number, since it uses as much as digits as its factorization.

1671665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 334338.

The product of its digits is 7560, while the sum is 32.

The square root of 1671665 is about 1292.9288456833. The cubic root of 1671665 is about 118.6815154517.

The spelling of 1671665 in words is "one million, six hundred seventy-one thousand, six hundred sixty-five".