20709539 has 2 divisors, whose sum is σ = 20709540. Its totient is φ = 20709538.

The previous prime is 20709523. The next prime is 20709547. The reversal of 20709539 is 93590702.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20709539 - 2⁴ = 20709523 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20709499 and 20709508.

It is not a weakly prime, because it can be changed into another prime (20709569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10354769 + 10354770.

It is an arithmetic number, because the mean of its divisors is an integer number (10354770).

Almost surely, 2^20709539 is an apocalyptic number.

20709539 is a deficient number, since it is larger than the sum of its proper divisors (1).

20709539 is an equidigital number, since it uses as much as digits as its factorization.

20709539 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17010, while the sum is 35.

The square root of 20709539 is about 4550.7734507444. The cubic root of 20709539 is about 274.6145078074.

The spelling of 20709539 in words is "twenty million, seven hundred nine thousand, five hundred thirty-nine".