65500015600721 has 12 divisors (see below), whose sum is σ = 72264279809628. Its totient is φ = 59320768837824.

The previous prime is 65500015600699. The next prime is 65500015600753. The reversal of 65500015600721 is 12700651000556.

It can be written as a sum of positive squares in 6 ways, for example, as 10385724390721 + 55114291210000 = 3222689^2 + 7423900^2 .

It is a de Polignac number, because none of the positive numbers 2^k-65500015600721 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (65500015603721) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3656350070 + ... + 3656367983.

It is an arithmetic number, because the mean of its divisors is an integer number (6022023317469).

Almost surely, 2^{65500015600721} is an apocalyptic number.

It is an amenable number.

65500015600721 is a deficient number, since it is larger than the sum of its proper divisors (6764264208907).

65500015600721 is a wasteful number, since it uses less digits than its factorization.

65500015600721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7312718132 (or 7312718119 counting only the distinct ones).

The product of its (nonzero) digits is 63000, while the sum is 38.

The spelling of 65500015600721 in words is "sixty-five trillion, five hundred billion, fifteen million, six hundred thousand, seven hundred twenty-one".