642838 has 32 divisors (see below), whose sum is σ = 1214784. Its totient is φ = 248832.

The previous prime is 642833. The next prime is 642853. The reversal of 642838 is 838246.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642833) by changing a digit.

642838 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 15 ways as a sum of consecutive naturals, for example, 8770 + ... + 8842.

It is an arithmetic number, because the mean of its divisors is an integer number (37962).

2⁶⁴²⁸³⁸ is an apocalyptic number.

642838 is a deficient number, since it is larger than the sum of its proper divisors (571946).

642838 is a wasteful number, since it uses less digits than its factorization.

642838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136.

The product of its digits is 9216, while the sum is 31.

The square root of 642838 is about 801.7717879796. The cubic root of 642838 is about 86.3045807298.

The spelling of 642838 in words is "six hundred forty-two thousand, eight hundred thirty-eight".