20951984 has 40 divisors (see below), whose sum is σ = 43799280. Its totient is φ = 9682560.

The previous prime is 20951981. The next prime is 20951993. The reversal of 20951984 is 48915902.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is not an unprimeable number, because it can be changed into a prime (20951981) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 511004 + ... + 511044.

It is an arithmetic number, because the mean of its divisors is an integer number (1094982).

Almost surely, 2^20951984 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20951984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21899640).

20951984 is an abundant number, since it is smaller than the sum of its proper divisors (22847296).

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

20951984 is an frugal number, since it uses more digits than its factorization.

20951984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150 (or 62 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 20951984 is about 4577.3337217205. Note that the first 3 decimals coincide. The cubic root of 20951984 is about 275.6819833575.

20951984 divided by its sum of digits (38) gives a cube (551368 = 82³).

The spelling of 20951984 in words is "twenty million, nine hundred fifty-one thousand, nine hundred eighty-four".