1665491 has 4 divisors (see below), whose sum is σ = 1675632. Its totient is φ = 1655352.

The previous prime is 1665479. The next prime is 1665493. The reversal of 1665491 is 1945661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1665491 - 2⁶ = 1665427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1665493) 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, 4820 + ... + 5153.

It is an arithmetic number, because the mean of its divisors is an integer number (418908).

2^1665491 is an apocalyptic number.

1665491 is a deficient number, since it is larger than the sum of its proper divisors (10141).

1665491 is an equidigital number, since it uses as much as digits as its factorization.

1665491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10140.

The product of its digits is 6480, while the sum is 32.

The square root of 1665491 is about 1290.5390346673. The cubic root of 1665491 is about 118.5352254527.

The spelling of 1665491 in words is "one million, six hundred sixty-five thousand, four hundred ninety-one".