66665890267 has 4 divisors (see below), whose sum is σ = 67758773776. Its totient is φ = 65573006760.

The previous prime is 66665890261. The next prime is 66665890297. The reversal of 66665890267 is 76209856666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 76209856666 = 2 ⋅38104928333.

It is a cyclic number.

It is not a de Polignac number, because 66665890267 - 2¹⁵ = 66665857499 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (61), and also a Moran number because the ratio is a prime number: 1092883447 = 66665890267 / (6 + 6 + 6 + 6 + 5 + 8 + 9 + 0 + 2 + 6 + 7).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66665890261) 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 3 ways as a sum of consecutive naturals, for example, 546441663 + ... + 546441784.

It is an arithmetic number, because the mean of its divisors is an integer number (16939693444).

Almost surely, 2^66665890267 is an apocalyptic number.

66665890267 is a deficient number, since it is larger than the sum of its proper divisors (1092883509).

66665890267 is a wasteful number, since it uses less digits than its factorization.

66665890267 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1092883508.

The product of its (nonzero) digits is 39191040, while the sum is 61.

The spelling of 66665890267 in words is "sixty-six billion, six hundred sixty-five million, eight hundred ninety thousand, two hundred sixty-seven".