65665105065721 has 8 divisors (see below), whose sum is σ = 75142918240704. Its totient is φ = 56211562860720.

The previous prime is 65665105065667. The next prime is 65665105065727. The reversal of 65665105065721 is 12756050156656.

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-65665105065721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65665105065727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6067736695 + ... + 6067747516.

It is an arithmetic number, because the mean of its divisors is an integer number (9392864780088).

Almost surely, 2^{65665105065721} is an apocalyptic number.

It is an amenable number.

65665105065721 is a deficient number, since it is larger than the sum of its proper divisors (9477813174983).

65665105065721 is a wasteful number, since it uses less digits than its factorization.

65665105065721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12135484991.

The product of its (nonzero) digits is 11340000, while the sum is 55.

The spelling of 65665105065721 in words is "sixty-five trillion, six hundred sixty-five billion, one hundred five million, sixty-five thousand, seven hundred twenty-one".