66515943821318 has 16 divisors (see below), whose sum is σ = 100243682950320. Its totient is φ = 33101626938336.

The previous prime is 66515943821311. The next prime is 66515943821339. The reversal of 66515943821318 is 81312834951566.

It is a super-2 number, since 2×66515943821318² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66515943821311) 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, 60479480 + ... + 61569467.

It is an arithmetic number, because the mean of its divisors is an integer number (6265230184395).

Almost surely, 2^{66515943821318} is an apocalyptic number.

66515943821318 is a deficient number, since it is larger than the sum of its proper divisors (33727739129002).

66515943821318 is a wasteful number, since it uses less digits than its factorization.

66515943821318 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122050231.

The product of its digits is 37324800, while the sum is 62.

The spelling of 66515943821318 in words is "sixty-six trillion, five hundred fifteen billion, nine hundred forty-three million, eight hundred twenty-one thousand, three hundred eighteen".