66520490938521 has 16 divisors (see below), whose sum is σ = 89159256261504. Its totient is φ = 44114435773184.

The previous prime is 66520490938513. The next prime is 66520490938673. The reversal of 66520490938521 is 12583909402566.

It is a cyclic number.

It is not a de Polignac number, because 66520490938521 - 2³ = 66520490938513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66520490938501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5992320 + ... + 12998033.

It is an arithmetic number, because the mean of its divisors is an integer number (5572453516344).

Almost surely, 2^{66520490938521} is an apocalyptic number.

It is an amenable number.

66520490938521 is a deficient number, since it is larger than the sum of its proper divisors (22638765322983).

66520490938521 is a wasteful number, since it uses less digits than its factorization.

66520490938521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18996480.

The product of its (nonzero) digits is 27993600, while the sum is 60.

The spelling of 66520490938521 in words is "sixty-six trillion, five hundred twenty billion, four hundred ninety million, nine hundred thirty-eight thousand, five hundred twenty-one".