21669964728697 has 8 divisors (see below), whose sum is σ = 21982517411400. Its totient is φ = 21359531047680.

The previous prime is 21669964728679. The next prime is 21669964728739. The reversal of 21669964728697 is 79682746996612.

It can be written as a sum of positive squares in 4 ways, for example, as 4898515401081 + 16771449327616 = 2213259^2 + 4095296^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21669964728697 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21669964728697.

It is not an unprimeable number, because it can be changed into a prime (21669964723697) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 529729822 + ... + 529770727.

It is an arithmetic number, because the mean of its divisors is an integer number (2747814676425).

Almost surely, 2^{21669964728697} is an apocalyptic number.

It is an amenable number.

21669964728697 is a deficient number, since it is larger than the sum of its proper divisors (312552682703).

21669964728697 is a wasteful number, since it uses less digits than its factorization.

21669964728697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1059500843.

The product of its digits is 5925685248, while the sum is 82.

The spelling of 21669964728697 in words is "twenty-one trillion, six hundred sixty-nine billion, nine hundred sixty-four million, seven hundred twenty-eight thousand, six hundred ninety-seven".