20949984 has 144 divisors (see below), whose sum is σ = 68992560. Its totient is φ = 5959680.

The previous prime is 20949953. The next prime is 20949991. The reversal of 20949984 is 48994902.

It is a tau number, because it is divible by the number of its divisors (144).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 53662 + ... + 54050.

It is an arithmetic number, because the mean of its divisors is an integer number (479115).

Almost surely, 2^20949984 is an apocalyptic number.

20949984 is a gapful number since it is divisible by the number (24) 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 20949984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34496280).

20949984 is an abundant number, since it is smaller than the sum of its proper divisors (48042576).

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

20949984 is a wasteful number, since it uses less digits than its factorization.

20949984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 433 (or 422 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 45.

The square root of 20949984 is about 4577.1152487129. The cubic root of 20949984 is about 275.6732112127.

The spelling of 20949984 in words is "twenty million, nine hundred forty-nine thousand, nine hundred eighty-four".