642868 has 12 divisors (see below), whose sum is σ = 1132740. Its totient is φ = 319232.

The previous prime is 642853. The next prime is 642869. The reversal of 642868 is 868246.

It can be written as a sum of positive squares in 2 ways, for example, as 268324 + 374544 = 518^2 + 612^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642869) 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, 228 + ... + 1156.

It is an arithmetic number, because the mean of its divisors is an integer number (94395).

2⁶⁴²⁸⁶⁸ is an apocalyptic number.

It is an amenable number.

642868 is a deficient number, since it is larger than the sum of its proper divisors (489872).

642868 is a wasteful number, since it uses less digits than its factorization.

642868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1106 (or 1104 counting only the distinct ones).

The product of its digits is 18432, while the sum is 34.

The square root of 642868 is about 801.7904963268. The cubic root of 642868 is about 86.3059232646.

The spelling of 642868 in words is "six hundred forty-two thousand, eight hundred sixty-eight".