998663 has 4 divisors (see below), whose sum is σ = 1003608. Its totient is φ = 993720.

The previous prime is 998653. The next prime is 998681. The reversal of 998663 is 366899.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-998663 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 998663.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (998623) 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, 2156 + ... + 2577.

It is an arithmetic number, because the mean of its divisors is an integer number (250902).

2⁹⁹⁸⁶⁶³ is an apocalyptic number.

998663 is a deficient number, since it is larger than the sum of its proper divisors (4945).

998663 is a wasteful number, since it uses less digits than its factorization.

998663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4944.

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

The square root of 998663 is about 999.3312764044. The cubic root of 998663 is about 99.9554134567.

It can be divided in two parts, 998 and 663, that added together give a palindrome (1661).

The spelling of 998663 in words is "nine hundred ninety-eight thousand, six hundred sixty-three".