998643 has 4 divisors (see below), whose sum is σ = 1331528. Its totient is φ = 665760.

The previous prime is 998633. The next prime is 998651. The reversal of 998643 is 346899.

998643 is nontrivially palindromic in base 8.

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

It is not a de Polignac number, because 998643 - 2¹⁷ = 867571 is a prime.

It is a D-number.

It is a Duffinian number.

998643 is an undulating number in base 8.

It is a nialpdrome in base 10.

It is a zygodrome in base 2.

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, 166438 + ... + 166443.

It is an arithmetic number, because the mean of its divisors is an integer number (332882).

2⁹⁹⁸⁶⁴³ is an apocalyptic number.

998643 is a deficient number, since it is larger than the sum of its proper divisors (332885).

998643 is a wasteful number, since it uses less digits than its factorization.

998643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332884.

The product of its digits is 46656, while the sum is 39.

The square root of 998643 is about 999.3212696626. The cubic root of 998643 is about 99.9547461907.

The spelling of 998643 in words is "nine hundred ninety-eight thousand, six hundred forty-three".