642544123 has 16 divisors (see below), whose sum is σ = 729239616. Its totient is φ = 561686400.

The previous prime is 642544081. The next prime is 642544129. The reversal of 642544123 is 321445246.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642544123 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642544129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19561 + ... + 40837.

It is an arithmetic number, because the mean of its divisors is an integer number (45577476).

Almost surely, 2^642544123 is an apocalyptic number.

642544123 is a deficient number, since it is larger than the sum of its proper divisors (86695493).

642544123 is a wasteful number, since it uses less digits than its factorization.

642544123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21414.

The product of its digits is 23040, while the sum is 31.

The square root of 642544123 is about 25348.4540554252. The cubic root of 642544123 is about 862.9142718406.

Adding to 642544123 its reverse (321445246), we get a palindrome (963989369).

The spelling of 642544123 in words is "six hundred forty-two million, five hundred forty-four thousand, one hundred twenty-three".