998642 has 4 divisors (see below), whose sum is σ = 1497966. Its totient is φ = 499320.

The previous prime is 998633. The next prime is 998651. The reversal of 998642 is 246899.

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

It is an interprime number because it is at equal distance from previous prime (998633) and next prime (998651).

It can be written as a sum of positive squares in only one way, i.e., 919681 + 78961 = 959^2 + 281^2 .

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 998596 and 998605.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 249659 + ... + 249662.

2⁹⁹⁸⁶⁴² is an apocalyptic number.

998642 is a deficient number, since it is larger than the sum of its proper divisors (499324).

998642 is a wasteful number, since it uses less digits than its factorization.

998642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 499323.

The product of its digits is 31104, while the sum is 38.

The square root of 998642 is about 999.3207693228. The cubic root of 998642 is about 99.9547128271.

It can be divided in two parts, 99 and 8642, that multiplied together give a palindrome (855558).

The spelling of 998642 in words is "nine hundred ninety-eight thousand, six hundred forty-two".