20802309 has 16 divisors (see below), whose sum is σ = 31302720. Its totient is φ = 12172160.

The previous prime is 20802307. The next prime is 20802311. The reversal of 20802309 is 90320802.

It is an interprime number because it is at equal distance from previous prime (20802307) and next prime (20802311).

It is not a de Polignac number, because 20802309 - 2¹ = 20802307 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20802307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9912 + ... + 11825.

It is an arithmetic number, because the mean of its divisors is an integer number (1956420).

Almost surely, 2^20802309 is an apocalyptic number.

20802309 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

20802309 is a deficient number, since it is larger than the sum of its proper divisors (10500411).

20802309 is a wasteful number, since it uses less digits than its factorization.

20802309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21780.

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 20802309 is about 4560.9548342425. The cubic root of 20802309 is about 275.0239494294.

The spelling of 20802309 in words is "twenty million, eight hundred two thousand, three hundred nine".