663855 has 8 divisors (see below), whose sum is σ = 1062192. Its totient is φ = 354048.

The previous prime is 663853. The next prime is 663857. The reversal of 663855 is 558366.

It is an interprime number because it is at equal distance from previous prime (663853) and next prime (663857).

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

It is not a de Polignac number, because 663855 - 2¹ = 663853 is a prime.

It is a super-2 number, since 2×663855² = 881406922050, which contains 22 as substring.

663855 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663853) 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, 22114 + ... + 22143.

It is an arithmetic number, because the mean of its divisors is an integer number (132774).

2⁶⁶³⁸⁵⁵ is an apocalyptic number.

663855 is a deficient number, since it is larger than the sum of its proper divisors (398337).

663855 is a wasteful number, since it uses less digits than its factorization.

663855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44265.

The product of its digits is 21600, while the sum is 33.

The square root of 663855 is about 814.7729745150. The cubic root of 663855 is about 87.2350625627.

Adding to 663855 its reverse (558366), we get a palindrome (1222221).

The spelling of 663855 in words is "six hundred sixty-three thousand, eight hundred fifty-five".