20839840 has 96 divisors (see below), whose sum is σ = 58786560. Its totient is φ = 6825984.

The previous prime is 20839829. The next prime is 20839867. The reversal of 20839840 is 4893802.

It is a junction number, because it is equal to n+sod(n) for n = 20839796 and 20839805.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25356 + ... + 26164.

It is an arithmetic number, because the mean of its divisors is an integer number (612360).

Almost surely, 2^20839840 is an apocalyptic number.

20839840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20839840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29393280).

20839840 is an abundant number, since it is smaller than the sum of its proper divisors (37946720).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20839840 is a wasteful number, since it uses less digits than its factorization.

20839840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 854 (or 846 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 20839840 is about 4565.0673598535. The cubic root of 20839840 is about 275.1892471461.

The spelling of 20839840 in words is "twenty million, eight hundred thirty-nine thousand, eight hundred forty".