12820658866 has 4 divisors (see below), whose sum is σ = 19230988302. Its totient is φ = 6410329432.

The previous prime is 12820658863. The next prime is 12820658867. The reversal of 12820658866 is 66885602821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 66885602821 = 31 ⋅2157600091.

It can be written as a sum of positive squares in only one way, i.e., 6670805625 + 6149853241 = 81675^2 + 78421^2 .

It is not an unprimeable number, because it can be changed into a prime (12820658863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3205164715 + ... + 3205164718.

Almost surely, 2^12820658866 is an apocalyptic number.

12820658866 is a deficient number, since it is larger than the sum of its proper divisors (6410329436).

12820658866 is an equidigital number, since it uses as much as digits as its factorization.

12820658866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6410329435.

The product of its (nonzero) digits is 2211840, while the sum is 52.

The spelling of 12820658866 in words is "twelve billion, eight hundred twenty million, six hundred fifty-eight thousand, eight hundred sixty-six".