642938 has 4 divisors (see below), whose sum is σ = 964410. Its totient is φ = 321468.

The previous prime is 642937. The next prime is 642947. The reversal of 642938 is 839246.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 839246 = 2 ⋅419623.

It can be written as a sum of positive squares in only one way, i.e., 405769 + 237169 = 637^2 + 487^2 .

It is a d-powerful number, because it can be written as 6² + 4 + 9⁵ + 2¹⁹ + 3¹⁰ + 8³ .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (642931) 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 as a sum of consecutive naturals, namely, 160733 + ... + 160736.

2⁶⁴²⁹³⁸ is an apocalyptic number.

642938 is a deficient number, since it is larger than the sum of its proper divisors (321472).

642938 is a wasteful number, since it uses less digits than its factorization.

642938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321471.

The product of its digits is 10368, while the sum is 32.

The square root of 642938 is about 801.8341474395. The cubic root of 642938 is about 86.3090556834.

The spelling of 642938 in words is "six hundred forty-two thousand, nine hundred thirty-eight".