66345715216520 has 16 divisors (see below), whose sum is σ = 149277859237260. Its totient is φ = 26538286086592.

The previous prime is 66345715216481. The next prime is 66345715216553. The reversal of 66345715216520 is 2561251754366.

It can be written as a sum of positive squares in 2 ways, for example, as 60151161695524 + 6194553520996 = 7755718^2 + 2488886^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 829321440167 + ... + 829321440246.

Almost surely, 2^{66345715216520} is an apocalyptic number.

It is an amenable number.

66345715216520 is an abundant number, since it is smaller than the sum of its proper divisors (82932144020740).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66345715216520 is a wasteful number, since it uses less digits than its factorization.

66345715216520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1658642880424 (or 1658642880420 counting only the distinct ones).

The product of its (nonzero) digits is 9072000, while the sum is 53.

The spelling of 66345715216520 in words is "sixty-six trillion, three hundred forty-five billion, seven hundred fifteen million, two hundred sixteen thousand, five hundred twenty".