66686450161 has 4 divisors (see below), whose sum is σ = 66940011072. Its totient is φ = 66432889252.

The previous prime is 66686450153. The next prime is 66686450189. The reversal of 66686450161 is 16105468666.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66686450161 - 2³ = 66686450153 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66686450191) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 126780061 + ... + 126780586.

It is an arithmetic number, because the mean of its divisors is an integer number (16735002768).

Almost surely, 2^66686450161 is an apocalyptic number.

It is an amenable number.

66686450161 is a deficient number, since it is larger than the sum of its proper divisors (253560911).

66686450161 is a wasteful number, since it uses less digits than its factorization.

66686450161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253560910.

The product of its (nonzero) digits is 1244160, while the sum is 49.

The spelling of 66686450161 in words is "sixty-six billion, six hundred eighty-six million, four hundred fifty thousand, one hundred sixty-one".