642635661565 has 8 divisors (see below), whose sum is σ = 771167789280. Its totient is φ = 514105198992.

The previous prime is 642635661559. The next prime is 642635661581. The reversal of 642635661565 is 565166536246.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 642635661565 - 2³ = 642635661557 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 709606 + ... + 1337464.

It is an arithmetic number, because the mean of its divisors is an integer number (96395973660).

Almost surely, 2^642635661565 is an apocalyptic number.

It is an amenable number.

642635661565 is a deficient number, since it is larger than the sum of its proper divisors (128532127715).

642635661565 is a wasteful number, since it uses less digits than its factorization.

642635661565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 832571.

The product of its digits is 23328000, while the sum is 55.

The spelling of 642635661565 in words is "six hundred forty-two billion, six hundred thirty-five million, six hundred sixty-one thousand, five hundred sixty-five".