642239317 has 4 divisors (see below), whose sum is σ = 642362796. Its totient is φ = 642115840.

The previous prime is 642239263. The next prime is 642239321. The reversal of 642239317 is 713932246.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 367143921 + 275095396 = 19161^2 + 16586^2 .

It is a cyclic number.

It is not a de Polignac number, because 642239317 - 2¹¹ = 642237269 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642239347) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53578 + ... + 64459.

It is an arithmetic number, because the mean of its divisors is an integer number (160590699).

Almost surely, 2^642239317 is an apocalyptic number.

It is an amenable number.

642239317 is a deficient number, since it is larger than the sum of its proper divisors (123479).

642239317 is a wasteful number, since it uses less digits than its factorization.

642239317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123478.

The product of its digits is 54432, while the sum is 37.

The square root of 642239317 is about 25342.4410229165. The cubic root of 642239317 is about 862.7778023286. Note that the first 3 decimals are identical.

The spelling of 642239317 in words is "six hundred forty-two million, two hundred thirty-nine thousand, three hundred seventeen".