1665601 has 8 divisors (see below), whose sum is σ = 1912640. Its totient is φ = 1420848.

The previous prime is 1665583. The next prime is 1665611. The reversal of 1665601 is 1065661.

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

It is a cyclic number.

It is not a de Polignac number, because 1665601 - 2⁵ = 1665569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1665611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1510 + ... + 2368.

It is an arithmetic number, because the mean of its divisors is an integer number (239080).

2^1665601 is an apocalyptic number.

It is an amenable number.

1665601 is a deficient number, since it is larger than the sum of its proper divisors (247039).

1665601 is an equidigital number, since it uses as much as digits as its factorization.

1665601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1143.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 1665601 is about 1290.5816518144. The cubic root of 1665601 is about 118.5378350111.

Adding to 1665601 its product of nonzero digits (1080), we get a square (1666681 = 1291²).

The spelling of 1665601 in words is "one million, six hundred sixty-five thousand, six hundred one".