20709289 has 2 divisors, whose sum is σ = 20709290. Its totient is φ = 20709288.

The previous prime is 20709253. The next prime is 20709319. The reversal of 20709289 is 98290702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19536400 + 1172889 = 4420^2 + 1083^2 .

It is a cyclic number.

It is not a de Polignac number, because 20709289 - 2⁹ = 20708777 is a prime.

It is not a weakly prime, because it can be changed into another prime (20709239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10354644 + 10354645.

It is an arithmetic number, because the mean of its divisors is an integer number (10354645).

Almost surely, 2^20709289 is an apocalyptic number.

It is an amenable number.

20709289 is a deficient number, since it is larger than the sum of its proper divisors (1).

20709289 is an equidigital number, since it uses as much as digits as its factorization.

20709289 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 37.

The square root of 20709289 is about 4550.7459828033. The cubic root of 20709289 is about 274.6134027787.

The spelling of 20709289 in words is "twenty million, seven hundred nine thousand, two hundred eighty-nine".