1663405 has 8 divisors (see below), whose sum is σ = 2034072. Its totient is φ = 1305408.

The previous prime is 1663397. The next prime is 1663457. The reversal of 1663405 is 5043661.

It can be written as a sum of positive squares in 4 ways, for example, as 777924 + 885481 = 882^2 + 941^2 .

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 1663405 - 2³ = 1663397 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1663405.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2874 + ... + 3403.

It is an arithmetic number, because the mean of its divisors is an integer number (254259).

2^1663405 is an apocalyptic number.

It is an amenable number.

1663405 is a deficient number, since it is larger than the sum of its proper divisors (370667).

1663405 is an equidigital number, since it uses as much as digits as its factorization.

1663405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6335.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 1663405 is about 1289.7305920230. The cubic root of 1663405 is about 118.4857169727.

The spelling of 1663405 in words is "one million, six hundred sixty-three thousand, four hundred five".