20545709 has 2 divisors, whose sum is σ = 20545710. Its totient is φ = 20545708.

The previous prime is 20545699. The next prime is 20545711. The reversal of 20545709 is 90754502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18361225 + 2184484 = 4285^2 + 1478^2 .

It is a cyclic number.

It is not a de Polignac number, because 20545709 - 2¹² = 20541613 is a prime.

Together with 20545711, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20545769) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10272854 + 10272855.

It is an arithmetic number, because the mean of its divisors is an integer number (10272855).

Almost surely, 2^20545709 is an apocalyptic number.

It is an amenable number.

20545709 is a deficient number, since it is larger than the sum of its proper divisors (1).

20545709 is an equidigital number, since it uses as much as digits as its factorization.

20545709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12600, while the sum is 32.

The square root of 20545709 is about 4532.7374730950. The cubic root of 20545709 is about 273.8884453623. Note that the first 3 decimals are identical.

The spelling of 20545709 in words is "twenty million, five hundred forty-five thousand, seven hundred nine".