66786781658 has 16 divisors (see below), whose sum is σ = 101078684136. Its totient is φ = 33093957120.

The previous prime is 66786781643. The next prime is 66786781739. The reversal of 66786781658 is 85618768766.

It can be written as a sum of positive squares in 4 ways, for example, as 27540398209 + 39246383449 = 165953^2 + 198107^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3217160 + ... + 3237852.

Almost surely, 2^66786781658 is an apocalyptic number.

66786781658 is a deficient number, since it is larger than the sum of its proper divisors (34291902478).

66786781658 is a wasteful number, since it uses less digits than its factorization.

66786781658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35089.

The product of its digits is 162570240, while the sum is 68.

The spelling of 66786781658 in words is "sixty-six billion, seven hundred eighty-six million, seven hundred eighty-one thousand, six hundred fifty-eight".