642643680561 has 8 divisors (see below), whose sum is σ = 857314752384. Its totient is φ = 428200864560.

The previous prime is 642643680557. The next prime is 642643680589. The reversal of 642643680561 is 165086346246.

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

It is not a de Polignac number, because 642643680561 - 2² = 642643680557 is a prime.

It is not an unprimeable number, because it can be changed into a prime (642643680541) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 57057385 + ... + 57068646.

It is an arithmetic number, because the mean of its divisors is an integer number (107164344048).

Almost surely, 2^642643680561 is an apocalyptic number.

It is an amenable number.

642643680561 is a deficient number, since it is larger than the sum of its proper divisors (214671071823).

642643680561 is a wasteful number, since it uses less digits than its factorization.

642643680561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114127911.

The product of its (nonzero) digits is 4976640, while the sum is 51.

The spelling of 642643680561 in words is "six hundred forty-two billion, six hundred forty-three million, six hundred eighty thousand, five hundred sixty-one".