642568439 has 2 divisors, whose sum is σ = 642568440. Its totient is φ = 642568438.

The previous prime is 642568373. The next prime is 642568453. The reversal of 642568439 is 934865246.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 642568439 - 2²⁰ = 641519863 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 642568393 and 642568402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642568939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321284219 + 321284220.

It is an arithmetic number, because the mean of its divisors is an integer number (321284220).

Almost surely, 2^642568439 is an apocalyptic number.

642568439 is a deficient number, since it is larger than the sum of its proper divisors (1).

642568439 is an equidigital number, since it uses as much as digits as its factorization.

642568439 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1244160, while the sum is 47.

The square root of 642568439 is about 25348.9336856602. The cubic root of 642568439 is about 862.9251568823.

The spelling of 642568439 in words is "six hundred forty-two million, five hundred sixty-eight thousand, four hundred thirty-nine".