66127665409 has 27 divisors (see below), whose sum is σ = 72637499907. Its totient is φ = 60173802000.

The previous prime is 66127665391. The next prime is 66127665547. The reversal of 66127665409 is 90456672166.

It is a happy number.

The square root of 66127665409 is 257153.

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

It can be written as a sum of positive squares in only one way, i.e., 9782199025 + 56345466384 = 98905^2 + 237372^2 .

It is not a de Polignac number, because 66127665409 - 2⁵ = 66127665377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66127663409) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 437931484 + ... + 437931634.

Almost surely, 2^66127665409 is an apocalyptic number.

66127665409 is the 257153-rd square number.

66127665409 is the 128577-th centered octagonal number.

It is an amenable number.

66127665409 is a deficient number, since it is larger than the sum of its proper divisors (6509834498).

66127665409 is an equidigital number, since it uses as much as digits as its factorization.

66127665409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 590 (or 295 counting only the distinct ones).

The product of its (nonzero) digits is 3265920, while the sum is 52.

The spelling of 66127665409 in words is "sixty-six billion, one hundred twenty-seven million, six hundred sixty-five thousand, four hundred nine".