642509039 has 4 divisors (see below), whose sum is σ = 647199024. Its totient is φ = 637819056.

The previous prime is 642509011. The next prime is 642509041. The reversal of 642509039 is 930905246.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642509039 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 642508993 and 642509011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642509099) 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, 2344787 + ... + 2345060.

It is an arithmetic number, because the mean of its divisors is an integer number (161799756).

Almost surely, 2^642509039 is an apocalyptic number.

642509039 is a deficient number, since it is larger than the sum of its proper divisors (4689985).

642509039 is a wasteful number, since it uses less digits than its factorization.

642509039 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4689984.

The product of its (nonzero) digits is 58320, while the sum is 38.

The square root of 642509039 is about 25347.7620116649. The cubic root of 642509039 is about 862.8985660266.

The spelling of 642509039 in words is "six hundred forty-two million, five hundred nine thousand, thirty-nine".