642503665 has 4 divisors (see below), whose sum is σ = 771004404. Its totient is φ = 514002928.

The previous prime is 642503623. The next prime is 642503699. The reversal of 642503665 is 566305246.

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 279524961 + 362978704 = 16719^2 + 19052^2 .

It is a cyclic number.

It is not a de Polignac number, because 642503665 - 2²³ = 634115057 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 64250362 + ... + 64250371.

It is an arithmetic number, because the mean of its divisors is an integer number (192751101).

Almost surely, 2^642503665 is an apocalyptic number.

It is an amenable number.

642503665 is a deficient number, since it is larger than the sum of its proper divisors (128500739).

642503665 is a wasteful number, since it uses less digits than its factorization.

642503665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128500738.

The product of its (nonzero) digits is 129600, while the sum is 37.

The square root of 642503665 is about 25347.6560060294. The cubic root of 642503665 is about 862.8961602343.

The spelling of 642503665 in words is "six hundred forty-two million, five hundred three thousand, six hundred sixty-five".