66550532938201 has 27 divisors (see below), whose sum is σ = 72484842999933. Its totient is φ = 61074240982560.

The previous prime is 66550532938157. The next prime is 66550532938207. The reversal of 66550532938201 is 10283923505566.

It is a happy number.

The square root of 66550532938201 is 8157851.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 51256364016025 + 15294168922176 = 7159355^2 + 3910776^2 .

It is not a de Polignac number, because 66550532938201 - 2²⁵ = 66550499383769 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66550532938207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 19195421670 + ... + 19195425136.

Almost surely, 2^{66550532938201} is an apocalyptic number.

66550532938201 is the 8157851-st square number.

66550532938201 is the 4078926-th centered octagonal number.

It is an amenable number.

66550532938201 is a deficient number, since it is larger than the sum of its proper divisors (5934310061732).

66550532938201 is an frugal number, since it uses more digits than its factorization.

66550532938201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7322 (or 3661 counting only the distinct ones).

The product of its (nonzero) digits is 11664000, while the sum is 55.

The spelling of 66550532938201 in words is "sixty-six trillion, five hundred fifty billion, five hundred thirty-two million, nine hundred thirty-eight thousand, two hundred one".