66561610205195 has 32 divisors (see below), whose sum is σ = 91749797732736. Its totient is φ = 45409604889600.

The previous prime is 66561610205159. The next prime is 66561610205203. The reversal of 66561610205195 is 59150201616566.

It is not a de Polignac number, because 66561610205195 - 2¹⁸ = 66561609943051 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 522722135 + ... + 522849455.

It is an arithmetic number, because the mean of its divisors is an integer number (2867181179148).

Almost surely, 2^{66561610205195} is an apocalyptic number.

66561610205195 is a deficient number, since it is larger than the sum of its proper divisors (25188187527541).

66561610205195 is a wasteful number, since it uses less digits than its factorization.

66561610205195 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203351.

The product of its (nonzero) digits is 2916000, while the sum is 53.

The spelling of 66561610205195 in words is "sixty-six trillion, five hundred sixty-one billion, six hundred ten million, two hundred five thousand, one hundred ninety-five".