1663399 has 4 divisors (see below), whose sum is σ = 1761264. Its totient is φ = 1565536.

The previous prime is 1663397. The next prime is 1663457. The reversal of 1663399 is 9933661.

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 1663399 - 2¹ = 1663397 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1663391) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 48907 + ... + 48940.

It is an arithmetic number, because the mean of its divisors is an integer number (440316).

2^1663399 is an apocalyptic number.

1663399 is a deficient number, since it is larger than the sum of its proper divisors (97865).

1663399 is an equidigital number, since it uses as much as digits as its factorization.

1663399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97864.

The product of its digits is 26244, while the sum is 37.

The square root of 1663399 is about 1289.7282659537. The cubic root of 1663399 is about 118.4855745109.

The spelling of 1663399 in words is "one million, six hundred sixty-three thousand, three hundred ninety-nine".