20566613 has 2 divisors, whose sum is σ = 20566614. Its totient is φ = 20566612.

The previous prime is 20566591. The next prime is 20566631. The reversal of 20566613 is 31666502.

Together with next prime (20566631) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18472804 + 2093809 = 4298^2 + 1447^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20566613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20566673) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10283306 + 10283307.

It is an arithmetic number, because the mean of its divisors is an integer number (10283307).

Almost surely, 2^20566613 is an apocalyptic number.

It is an amenable number.

20566613 is a deficient number, since it is larger than the sum of its proper divisors (1).

20566613 is an equidigital number, since it uses as much as digits as its factorization.

20566613 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 29.

The square root of 20566613 is about 4535.0427781885. The cubic root of 20566613 is about 273.9813021144.

The spelling of 20566613 in words is "twenty million, five hundred sixty-six thousand, six hundred thirteen".