66220594691 has 4 divisors (see below), whose sum is σ = 66534436584. Its totient is φ = 65906752800.

The previous prime is 66220594673. The next prime is 66220594777. The reversal of 66220594691 is 19649502266.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66220594691 - 2³⁰ = 65146852867 is a prime.

It is a super-2 number, since 2×66220594691² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66220594651) 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 3 ways as a sum of consecutive naturals, for example, 156920630 + ... + 156921051.

It is an arithmetic number, because the mean of its divisors is an integer number (16633609146).

Almost surely, 2^66220594691 is an apocalyptic number.

66220594691 is a deficient number, since it is larger than the sum of its proper divisors (313841893).

66220594691 is a wasteful number, since it uses less digits than its factorization.

66220594691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 313841892.

The product of its (nonzero) digits is 1399680, while the sum is 50.

The spelling of 66220594691 in words is "sixty-six billion, two hundred twenty million, five hundred ninety-four thousand, six hundred ninety-one".