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21058420 = 2254161421
BaseRepresentation
bin101000001010…
…1001101110100
31110121212201111
41100111031310
520342332140
62031204404
7343664545
oct120251564
943555644
1021058420
1110983559
127076704
134494106
142b224cc
151cae7ea
hex1415374

21058420 has 48 divisors (see below), whose sum is σ = 46153296. Its totient is φ = 8064000.

The previous prime is 21058417. The next prime is 21058447. The reversal of 21058420 is 2485012.

It can be written as a sum of positive squares in 8 ways, for example, as 15163236 + 5895184 = 3894^2 + 2428^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21058391 and 21058400.

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 15 ways as a sum of consecutive naturals, for example, 49810 + ... + 50230.

It is an arithmetic number, because the mean of its divisors is an integer number (961527).

It is a vampire number, since it can be written as 25018420 (with its own digits).

Almost surely, 221058420 is an apocalyptic number.

21058420 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 21058420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23076648).

21058420 is an abundant number, since it is smaller than the sum of its proper divisors (25094876).

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

21058420 is a wasteful number, since it uses less digits than its factorization.

21058420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 532 (or 530 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 22.

The square root of 21058420 is about 4588.9454126193. The cubic root of 21058420 is about 276.1480162442.

It can be divided in two parts, 2105 and 8420, that multiplied together give a square (17724100 = 42102).

The spelling of 21058420 in words is "twenty-one million, fifty-eight thousand, four hundred twenty".

Divisors: 1 2 4 5 10 20 41 61 82 122 164 205 244 305 410 421 610 820 842 1220 1684 2105 2501 4210 5002 8420 10004 12505 17261 25010 25681 34522 50020 51362 69044 86305 102724 128405 172610 256810 345220 513620 1052921 2105842 4211684 5264605 10529210 21058420