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20721248 = 2519173197
BaseRepresentation
bin100111100001…
…0111001100000
31102222202012122
41033002321200
520301034443
62020043412
7341061542
oct117027140
942882178
1020721248
11107731a9
126b33568
1343a67c2
142a75692
151c44968
hex13c2e60

20721248 has 48 divisors (see below), whose sum is σ = 43409520. Its totient is φ = 9709056.

The previous prime is 20721223. The next prime is 20721263. The reversal of 20721248 is 84212702.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 105086 + ... + 105282.

It is an arithmetic number, because the mean of its divisors is an integer number (904365).

Almost surely, 220721248 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 20721248, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21704760).

20721248 is an abundant number, since it is smaller than the sum of its proper divisors (22688272).

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

20721248 is a wasteful number, since it uses less digits than its factorization.

20721248 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 399 (or 391 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 26.

The square root of 20721248 is about 4552.0597535621. The cubic root of 20721248 is about 274.6662529712. Note that the first 3 decimals are identical.

The spelling of 20721248 in words is "twenty million, seven hundred twenty-one thousand, two hundred forty-eight".

Divisors: 1 2 4 8 16 19 32 38 76 152 173 197 304 346 394 608 692 788 1384 1576 2768 3152 3287 3743 5536 6304 6574 7486 13148 14972 26296 29944 34081 52592 59888 68162 105184 119776 136324 272648 545296 647539 1090592 1295078 2590156 5180312 10360624 20721248