12820666 has 4 divisors (see below), whose sum is σ = 19231002. Its totient is φ = 6410332.

The previous prime is 12820657. The next prime is 12820679. The reversal of 12820666 is 66602821.

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

It can be written as a sum of positive squares in only one way, i.e., 9740641 + 3080025 = 3121^2 + 1755^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3205165 + ... + 3205168.

Almost surely, 2^12820666 is an apocalyptic number.

12820666 is a deficient number, since it is larger than the sum of its proper divisors (6410336).

12820666 is an equidigital number, since it uses as much as digits as its factorization.

12820666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6410335.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 12820666 is about 3580.5957604846. The cubic root of 12820666 is about 234.0472425130.

The spelling of 12820666 in words is "twelve million, eight hundred twenty thousand, six hundred sixty-six".