20611 has 2 divisors, whose sum is σ = 20612. Its totient is φ = 20610.

The previous prime is 20599. The next prime is 20627. The reversal of 20611 is 11602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20611 - 2⁷ = 20483 is a prime.

It is a Chen prime.

20611 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (20641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10305 + 10306.

It is an arithmetic number, because the mean of its divisors is an integer number (10306).

2²⁰⁶¹¹ is an apocalyptic number.

20611 is a deficient number, since it is larger than the sum of its proper divisors (1).

20611 is an equidigital number, since it uses as much as digits as its factorization.

20611 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 20611 is about 143.5653161456. The cubic root of 20611 is about 27.4178263240.

Subtracting from 20611 its reverse (11602), we obtain a palindrome (9009).

The spelling of 20611 in words is "twenty thousand, six hundred eleven".