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21100220 = 2251099679
BaseRepresentation
bin101000001111…
…1011010111100
31110201000001122
41100133122330
520400201340
62032130112
7344230451
oct120373274
943630048
1021100220
1110a019a9
127096938
1344aa14b
142b33828
151cbbdb5
hex141f6bc

21100220 has 24 divisors (see below), whose sum is σ = 44721600. Its totient is φ = 8361792.

The previous prime is 21100217. The next prime is 21100231. The reversal of 21100220 is 2200112.

It is a junction number, because it is equal to n+sod(n) for n = 21100198 and 21100207.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2660 + ... + 7019.

It is an arithmetic number, because the mean of its divisors is an integer number (1863400).

Almost surely, 221100220 is an apocalyptic number.

21100220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21100220 is an abundant number, since it is smaller than the sum of its proper divisors (23621380).

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

21100220 is a wasteful number, since it uses less digits than its factorization.

21100220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9797 (or 9795 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 8.

The square root of 21100220 is about 4593.4975780988. The cubic root of 21100220 is about 276.3306092095.

Adding to 21100220 its reverse (2200112), we get a palindrome (23300332).

The spelling of 21100220 in words is "twenty-one million, one hundred thousand, two hundred twenty".

Divisors: 1 2 4 5 10 20 109 218 436 545 1090 2180 9679 19358 38716 48395 96790 193580 1055011 2110022 4220044 5275055 10550110 21100220