2184664319721 has 63 divisors (see below), whose sum is σ = 3547683597927. Its totient is φ = 1344089550960.

The previous prime is 2184664319693. The next prime is 2184664319729. The reversal of 2184664319721 is 1279134664812.

The square root of 2184664319721 is 1478061.

It is a perfect power (a square), and thus also a powerful number.

2184664319721 is a `hidden beast` number, since 2 + 1 + 84 + 66 + 431 + 9 + 72 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 323175195225 + 1861489124496 = 568485^2 + 1364364^2 .

It is not a de Polignac number, because 2184664319721 - 2²³ = 2184655931113 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2184664319729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 62 ways as a sum of consecutive naturals, for example, 518797306 + ... + 518801516.

Almost surely, 2^{2184664319721} is an apocalyptic number.

2184664319721 is the 1478061-st square number.

2184664319721 is the 739031-st centered octagonal number.

It is an amenable number.

2184664319721 is a deficient number, since it is larger than the sum of its proper divisors (1363019278206).

2184664319721 is an frugal number, since it uses more digits than its factorization.

2184664319721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8466 (or 4227 counting only the distinct ones).

The product of its digits is 3483648, while the sum is 54.

The spelling of 2184664319721 in words is "two trillion, one hundred eighty-four billion, six hundred sixty-four million, three hundred nineteen thousand, seven hundred twenty-one".