642289 has 4 divisors (see below), whose sum is σ = 663040. Its totient is φ = 621540.

The previous prime is 642281. The next prime is 642359. The reversal of 642289 is 982246.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 642289 - 2³ = 642281 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 20719 = 642289 / (6 + 4 + 2 + 2 + 8 + 9).

It is a d-powerful number, because it can be written as 6⁶ + 4⁶ + 2¹³ + 2¹⁹ + 8 + 9⁵ .

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 642289.

It is not an unprimeable number, because it can be changed into a prime (642281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10329 + ... + 10390.

It is an arithmetic number, because the mean of its divisors is an integer number (165760).

2⁶⁴²²⁸⁹ is an apocalyptic number.

It is an amenable number.

642289 is a deficient number, since it is larger than the sum of its proper divisors (20751).

642289 is a wasteful number, since it uses less digits than its factorization.

642289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20750.

The product of its digits is 6912, while the sum is 31.

The square root of 642289 is about 801.4293481025. The cubic root of 642289 is about 86.2800049635.

The spelling of 642289 in words is "six hundred forty-two thousand, two hundred eighty-nine".