20869609 has 2 divisors, whose sum is σ = 20869610. Its totient is φ = 20869608.

The previous prime is 20869573. The next prime is 20869613. The reversal of 20869609 is 90696802.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19829209 + 1040400 = 4453^2 + 1020^2 .

It is a cyclic number.

It is not a de Polignac number, because 20869609 - 2⁹ = 20869097 is a prime.

It is not a weakly prime, because it can be changed into another prime (20869109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10434804 + 10434805.

It is an arithmetic number, because the mean of its divisors is an integer number (10434805).

Almost surely, 2^20869609 is an apocalyptic number.

It is an amenable number.

20869609 is a deficient number, since it is larger than the sum of its proper divisors (1).

20869609 is an equidigital number, since it uses as much as digits as its factorization.

20869609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 46656, while the sum is 40.

The square root of 20869609 is about 4568.3267177381. The cubic root of 20869609 is about 275.3202176186.

The spelling of 20869609 in words is "twenty million, eight hundred sixty-nine thousand, six hundred nine".