666796221 has 48 divisors (see below), whose sum is σ = 1188794880. Its totient is φ = 350714880.

The previous prime is 666796213. The next prime is 666796237. The reversal of 666796221 is 122697666.

It is not a de Polignac number, because 666796221 - 2³ = 666796213 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666796201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 352045 + ... + 353933.

It is an arithmetic number, because the mean of its divisors is an integer number (24766560).

Almost surely, 2^666796221 is an apocalyptic number.

It is an amenable number.

666796221 is a deficient number, since it is larger than the sum of its proper divisors (521998659).

666796221 is a wasteful number, since it uses less digits than its factorization.

666796221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2346 (or 2343 counting only the distinct ones).

The product of its digits is 326592, while the sum is 45.

The square root of 666796221 is about 25822.3976617200. The cubic root of 666796221 is about 873.6370491384.

It can be divided in two parts, 66679 and 6221, that added together give a square (72900 = 270²).

The spelling of 666796221 in words is "six hundred sixty-six million, seven hundred ninety-six thousand, two hundred twenty-one".