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21689472 = 27378069
BaseRepresentation
bin101001010111…
…1010010000000
31111210221100210
41102233102000
521023030342
62052514120
7352233420
oct122572200
944727323
1021689472
1111274692
12731b940
13465540c
142c48480
151d8679c
hex14af480

21689472 has 64 divisors (see below), whose sum is σ = 65851200. Its totient is φ = 6196224.

The previous prime is 21689471. The next prime is 21689497. The reversal of 21689472 is 27498612.

It is a tau number, because it is divible by the number of its divisors (64).

It is a self number, because there is not a number n which added to its sum of digits gives 21689472.

It is not an unprimeable number, because it can be changed into a prime (21689471) 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, 1347 + ... + 6722.

It is an arithmetic number, because the mean of its divisors is an integer number (1028925).

Almost surely, 221689472 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 21689472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32925600).

21689472 is an abundant number, since it is smaller than the sum of its proper divisors (44161728).

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

21689472 is an equidigital number, since it uses as much as digits as its factorization.

21689472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8093 (or 8081 counting only the distinct ones).

The product of its digits is 48384, while the sum is 39.

The square root of 21689472 is about 4657.1957227499. The cubic root of 21689472 is about 278.8793301474.

The spelling of 21689472 in words is "twenty-one million, six hundred eighty-nine thousand, four hundred seventy-two".

Divisors: 1 2 3 4 6 7 8 12 14 16 21 24 28 32 42 48 56 64 84 96 112 128 168 192 224 336 384 448 672 896 1344 2688 8069 16138 24207 32276 48414 56483 64552 96828 112966 129104 169449 193656 225932 258208 338898 387312 451864 516416 677796 774624 903728 1032832 1355592 1549248 1807456 2711184 3098496 3614912 5422368 7229824 10844736 21689472