20666573 has 2 divisors, whose sum is σ = 20666574. Its totient is φ = 20666572.

The previous prime is 20666567. The next prime is 20666599. The reversal of 20666573 is 37566602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20448484 + 218089 = 4522^2 + 467^2 .

It is a cyclic number.

It is not a de Polignac number, because 20666573 - 2⁴ = 20666557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20666533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10333286 + 10333287.

It is an arithmetic number, because the mean of its divisors is an integer number (10333287).

Almost surely, 2^20666573 is an apocalyptic number.

It is an amenable number.

20666573 is a deficient number, since it is larger than the sum of its proper divisors (1).

20666573 is an equidigital number, since it uses as much as digits as its factorization.

20666573 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 45360, while the sum is 35.

The square root of 20666573 is about 4546.0502636904. The cubic root of 20666573 is about 274.4244624342.

The spelling of 20666573 in words is "twenty million, six hundred sixty-six thousand, five hundred seventy-three".