20209689 has 16 divisors (see below), whose sum is σ = 30144640. Its totient is φ = 13381200.

The previous prime is 20209681. The next prime is 20209691. The reversal of 20209689 is 98690202.

It is not a de Polignac number, because 20209689 - 2³ = 20209681 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20209681) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1599 + ... + 6555.

It is an arithmetic number, because the mean of its divisors is an integer number (1884040).

Almost surely, 2^20209689 is an apocalyptic number.

It is an amenable number.

20209689 is a deficient number, since it is larger than the sum of its proper divisors (9934951).

20209689 is a wasteful number, since it uses less digits than its factorization.

20209689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5117 (or 5111 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 20209689 is about 4495.5187687296. The cubic root of 20209689 is about 272.3871047089.

The spelling of 20209689 in words is "twenty million, two hundred nine thousand, six hundred eighty-nine".