20666773321 has 2 divisors, whose sum is σ = 20666773322. Its totient is φ = 20666773320.

The previous prime is 20666773319. The next prime is 20666773357. The reversal of 20666773321 is 12337766602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12337655625 + 8329117696 = 111075^2 + 91264^2 .

It is a cyclic number.

It is not a de Polignac number, because 20666773321 - 2¹ = 20666773319 is a prime.

Together with 20666773319, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20666773921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10333386660 + 10333386661.

It is an arithmetic number, because the mean of its divisors is an integer number (10333386661).

Almost surely, 2^20666773321 is an apocalyptic number.

It is an amenable number.

20666773321 is a deficient number, since it is larger than the sum of its proper divisors (1).

20666773321 is an equidigital number, since it uses as much as digits as its factorization.

20666773321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 381024, while the sum is 43.

The spelling of 20666773321 in words is "twenty billion, six hundred sixty-six million, seven hundred seventy-three thousand, three hundred twenty-one".