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21905316 = 2234174197
BaseRepresentation
bin101001110001…
…1111110100100
31112012220110000
41103203332210
521101432231
62101301300
7354122616
oct123437644
945186400
1021905316
1111401874
127404830
1346cc734
142ca2db6
151dca6e6
hex14e3fa4

21905316 has 120 divisors (see below), whose sum is σ = 62752536. Its totient is φ = 6635520.

The previous prime is 21905297. The next prime is 21905321. The reversal of 21905316 is 61350912.

21905316 = 1933 + 1943 + 1953.

It can be written as a sum of positive squares in 4 ways, for example, as 1166400 + 20738916 = 1080^2 + 4554^2 .

It is a super-3 number, since 3×219053163 (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 21905316.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 225780 + ... + 225876.

Almost surely, 221905316 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 21905316, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31376268).

21905316 is an abundant number, since it is smaller than the sum of its proper divisors (40847220).

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

21905316 is a wasteful number, since it uses less digits than its factorization.

21905316 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171 (or 160 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 21905316 is about 4680.3115280930. The cubic root of 21905316 is about 279.8013727359.

The spelling of 21905316 in words is "twenty-one million, nine hundred five thousand, three hundred sixteen".

Divisors: 1 2 3 4 6 9 12 17 18 27 34 36 41 51 54 68 81 82 97 102 108 123 153 162 164 194 204 246 291 306 324 369 388 459 492 582 612 697 738 873 918 1107 1164 1377 1394 1476 1649 1746 1836 2091 2214 2619 2754 2788 3298 3321 3492 3977 4182 4428 4947 5238 5508 6273 6596 6642 7857 7954 8364 9894 10476 11931 12546 13284 14841 15714 15908 18819 19788 23862 25092 29682 31428 35793 37638 44523 47724 56457 59364 67609 71586 75276 89046 107379 112914 133569 135218 143172 178092 202827 214758 225828 267138 270436 322137 405654 429516 534276 608481 644274 811308 1216962 1288548 1825443 2433924 3650886 5476329 7301772 10952658 21905316