66147020645 has 16 divisors (see below), whose sum is σ = 79845076080. Its totient is φ = 52606041600.

The previous prime is 66147020617. The next prime is 66147020657. The reversal of 66147020645 is 54602074166.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 31103555044 + 35043465601 = 176362^2 + 187199^2 .

It is not a de Polignac number, because 66147020645 - 2¹² = 66147016549 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 566705 + ... + 673385.

It is an arithmetic number, because the mean of its divisors is an integer number (4990317255).

Almost surely, 2^66147020645 is an apocalyptic number.

It is an amenable number.

66147020645 is a deficient number, since it is larger than the sum of its proper divisors (13698055435).

66147020645 is a wasteful number, since it uses less digits than its factorization.

66147020645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107416.

The product of its (nonzero) digits is 241920, while the sum is 41.

The spelling of 66147020645 in words is "sixty-six billion, one hundred forty-seven million, twenty thousand, six hundred forty-five".