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21111212 = 2217310459
BaseRepresentation
bin101000010001…
…0000110101100
31110201120010202
41100202012230
520401024322
62032253032
7344304503
oct120420654
943646122
1021111212
1110a0a191
1270a1178
1344b2155
142b3783a
151cc0292
hex14221ac

21111212 has 12 divisors (see below), whose sum is σ = 39117960. Its totient is φ = 9934656.

The previous prime is 21111199. The next prime is 21111239. The reversal of 21111212 is 21211112.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 21111193 and 21111202.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 155162 + ... + 155297.

It is an arithmetic number, because the mean of its divisors is an integer number (3259830).

Almost surely, 221111212 is an apocalyptic number.

It is an amenable number.

21111212 is a deficient number, since it is larger than the sum of its proper divisors (18006748).

21111212 is a wasteful number, since it uses less digits than its factorization.

21111212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 310480 (or 310478 counting only the distinct ones).

The product of its digits is 8, while the sum is 11.

The square root of 21111212 is about 4594.6938962242. The cubic root of 21111212 is about 276.3785849932.

Adding to 21111212 its reverse (21211112), we get a palindrome (42322324).

The spelling of 21111212 in words is "twenty-one million, one hundred eleven thousand, two hundred twelve".

Divisors: 1 2 4 17 34 68 310459 620918 1241836 5277803 10555606 21111212