663899 has 4 divisors (see below), whose sum is σ = 668136. Its totient is φ = 659664.

The previous prime is 663893. The next prime is 663907. The reversal of 663899 is 998366.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 998366 = 2 ⋅499183.

It is a cyclic number.

It is not a de Polignac number, because 663899 - 2¹⁶ = 598363 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663893) 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, 1874 + ... + 2199.

It is an arithmetic number, because the mean of its divisors is an integer number (167034).

2⁶⁶³⁸⁹⁹ is an apocalyptic number.

663899 is a deficient number, since it is larger than the sum of its proper divisors (4237).

663899 is a wasteful number, since it uses less digits than its factorization.

663899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4236.

The product of its digits is 69984, while the sum is 41.

The square root of 663899 is about 814.7999754541. The cubic root of 663899 is about 87.2369898199.

The spelling of 663899 in words is "six hundred sixty-three thousand, eight hundred ninety-nine".