66338713818721 has 16 divisors (see below), whose sum is σ = 67858996278528. Its totient is φ = 64823034988800.

The previous prime is 66338713818719. The next prime is 66338713818739. The reversal of 66338713818721 is 12781831783366.

It is not a de Polignac number, because 66338713818721 - 2¹ = 66338713818719 is a prime.

It is a super-2 number, since 2×66338713818721² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66338713818121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87862411 + ... + 88614223.

It is an arithmetic number, because the mean of its divisors is an integer number (4241187267408).

Almost surely, 2^{66338713818721} is an apocalyptic number.

It is an amenable number.

66338713818721 is a deficient number, since it is larger than the sum of its proper divisors (1520282459807).

66338713818721 is a wasteful number, since it uses less digits than its factorization.

66338713818721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 754872.

The product of its digits is 48771072, while the sum is 64.

The spelling of 66338713818721 in words is "sixty-six trillion, three hundred thirty-eight billion, seven hundred thirteen million, eight hundred eighteen thousand, seven hundred twenty-one".