20899709 has 16 divisors (see below), whose sum is σ = 22982400. Its totient is φ = 18944640.

The previous prime is 20899699. The next prime is 20899721. The reversal of 20899709 is 90799802.

It is not a de Polignac number, because 20899709 - 2⁴ = 20899693 is a prime.

It is a Duffinian number.

It is a zygodrome in base 3.

It is a self number, because there is not a number n which added to its sum of digits gives 20899709.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20899789) 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, 34592 + ... + 35190.

It is an arithmetic number, because the mean of its divisors is an integer number (1436400).

Almost surely, 2^20899709 is an apocalyptic number.

It is an amenable number.

20899709 is a deficient number, since it is larger than the sum of its proper divisors (2082691).

20899709 is a wasteful number, since it uses less digits than its factorization.

20899709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 700.

The product of its (nonzero) digits is 81648, while the sum is 44.

The square root of 20899709 is about 4571.6199535832. The cubic root of 20899709 is about 275.4525177748.

The spelling of 20899709 in words is "twenty million, eight hundred ninety-nine thousand, seven hundred nine".