645221466 has 24 divisors (see below), whose sum is σ = 1435764564. Its totient is φ = 209260800.

The previous prime is 645221443. The next prime is 645221491. The reversal of 645221466 is 664122546.

645221466 is a `hidden beast` number, since 64 + 522 + 14 + 66 = 666.

645221466 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 638825625 + 6395841 = 25275^2 + 2529^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 645221466.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 483735 + ... + 485066.

Almost surely, 2^645221466 is an apocalyptic number.

645221466 is an abundant number, since it is smaller than the sum of its proper divisors (790543098).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645221466 is a wasteful number, since it uses less digits than its factorization.

645221466 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 968846 (or 968843 counting only the distinct ones).

The product of its digits is 69120, while the sum is 36.

The square root of 645221466 is about 25401.2099318123. The cubic root of 645221466 is about 864.1111370026. Note that the first 4 decimals are identical.

It can be divided in two parts, 645 and 221466, that added together give a triangular number (222111 = T₆₆₆).

The spelling of 645221466 in words is "six hundred forty-five million, two hundred twenty-one thousand, four hundred sixty-six".