66885904809 has 12 divisors (see below), whose sum is σ = 99224135556. Its totient is φ = 43385451552.

The previous prime is 66885904807. The next prime is 66885904859. The reversal of 66885904809 is 90840958866.

66885904809 is a `hidden beast` number, since 6 + 68 + 8 + 5 + 90 + 480 + 9 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 40130105625 + 26755799184 = 200325^2 + 163572^2 .

It is not a de Polignac number, because 66885904809 - 2¹ = 66885904807 is a prime.

It is a super-3 number, since 3×66885904809³ (a number of 33 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (66885904807) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 100428954 + ... + 100429619.

It is an arithmetic number, because the mean of its divisors is an integer number (8268677963).

Almost surely, 2^66885904809 is an apocalyptic number.

It is an amenable number.

66885904809 is a deficient number, since it is larger than the sum of its proper divisors (32338230747).

66885904809 is a wasteful number, since it uses less digits than its factorization.

66885904809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200858616 (or 200858613 counting only the distinct ones).

The product of its (nonzero) digits is 29859840, while the sum is 63.

The spelling of 66885904809 in words is "sixty-six billion, eight hundred eighty-five million, nine hundred four thousand, eight hundred nine".