642998 has 8 divisors (see below), whose sum is σ = 1015320. Its totient is φ = 304560.

The previous prime is 642997. The next prime is 643009. The reversal of 642998 is 899246.

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

It is a Harshad number since it is a multiple of its sum of digits (38), and also a Moran number because the ratio is a prime number: 16921 = 642998 / (6 + 4 + 2 + 9 + 9 + 8).

It is a d-powerful number, because it can be written as 6² + 4³ + 9⁵ + 2¹⁹ + 9⁵ + 8³ .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642997) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 8423 + ... + 8498.

It is an arithmetic number, because the mean of its divisors is an integer number (126915).

2⁶⁴²⁹⁹⁸ is an apocalyptic number.

642998 is a deficient number, since it is larger than the sum of its proper divisors (372322).

642998 is a wasteful number, since it uses less digits than its factorization.

642998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16942.

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

The square root of 642998 is about 801.8715607876. The cubic root of 642998 is about 86.3117404328.

The spelling of 642998 in words is "six hundred forty-two thousand, nine hundred ninety-eight".