642860918191 has 4 divisors (see below), whose sum is σ = 642995328352. Its totient is φ = 642726508032.

The previous prime is 642860918179. The next prime is 642860918209. The reversal of 642860918191 is 191819068246.

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

It is a cyclic number.

It is not a de Polignac number, because 642860918191 - 2¹⁷ = 642860787119 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 (642860418191) 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, 67197906 + ... + 67207471.

It is an arithmetic number, because the mean of its divisors is an integer number (160748832088).

Almost surely, 2^642860918191 is an apocalyptic number.

642860918191 is a deficient number, since it is larger than the sum of its proper divisors (134410161).

642860918191 is a wasteful number, since it uses less digits than its factorization.

642860918191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134410160.

The product of its (nonzero) digits is 1492992, while the sum is 55.

The spelling of 642860918191 in words is "six hundred forty-two billion, eight hundred sixty million, nine hundred eighteen thousand, one hundred ninety-one".