64780689665 has 8 divisors (see below), whose sum is σ = 80417408040. Its totient is φ = 50037498112.

The previous prime is 64780689643. The next prime is 64780689689. The reversal of 64780689665 is 56698608746.

It can be written as a sum of positive squares in 4 ways, for example, as 18362418064 + 46418271601 = 135508^2 + 215449^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64780689665 is a prime.

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, 223381544 + ... + 223381833.

It is an arithmetic number, because the mean of its divisors is an integer number (10052176005).

Almost surely, 2^64780689665 is an apocalyptic number.

It is an amenable number.

64780689665 is a deficient number, since it is larger than the sum of its proper divisors (15636718375).

64780689665 is a wasteful number, since it uses less digits than its factorization.

64780689665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 446763411.

The product of its (nonzero) digits is 104509440, while the sum is 65.

The spelling of 64780689665 in words is "sixty-four billion, seven hundred eighty million, six hundred eighty-nine thousand, six hundred sixty-five".