66986294209 has 4 divisors (see below), whose sum is σ = 67015766916. Its totient is φ = 66956821504.

The previous prime is 66986294201. The next prime is 66986294239. The reversal of 66986294209 is 90249268966.

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

It can be written as a sum of positive squares in 2 ways, for example, as 63956892609 + 3029401600 = 252897^2 + 55040^2 .

It is a cyclic number.

It is not a de Polignac number, because 66986294209 - 2³ = 66986294201 is a prime.

It is a super-2 number, since 2×66986294209² (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 (66986294201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14732944 + ... + 14737489.

It is an arithmetic number, because the mean of its divisors is an integer number (16753941729).

Almost surely, 2^66986294209 is an apocalyptic number.

It is an amenable number.

66986294209 is a deficient number, since it is larger than the sum of its proper divisors (29472707).

66986294209 is a wasteful number, since it uses less digits than its factorization.

66986294209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29472706.

The product of its (nonzero) digits is 20155392, while the sum is 61.

The spelling of 66986294209 in words is "sixty-six billion, nine hundred eighty-six million, two hundred ninety-four thousand, two hundred nine".