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21211212 = 223113743101
BaseRepresentation
bin101000011101…
…0100001001100
31110220122022110
41100322201030
520412224322
62034344020
7345202161
oct120724114
943818273
1021211212
1110a78330
12712b010
134518819
142b62068
151cdec0c
hex143a84c

21211212 has 96 divisors (see below), whose sum is σ = 57302784. Its totient is φ = 6048000.

The previous prime is 21211181. The next prime is 21211217.

21211212 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (12).

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

It is not an unprimeable number, because it can be changed into a prime (21211217) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 209962 + ... + 210062.

It is an arithmetic number, because the mean of its divisors is an integer number (596904).

Almost surely, 221211212 is an apocalyptic number.

21211212 is a gapful number since it is divisible by the number (22) 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 21211212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28651392).

21211212 is an abundant number, since it is smaller than the sum of its proper divisors (36091572).

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

21211212 is a wasteful number, since it uses less digits than its factorization.

21211212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199 (or 197 counting only the distinct ones).

The product of its digits is 16, while the sum is 12.

The square root of 21211212 is about 4605.5631577474. The cubic root of 21211212 is about 276.8142829288.

It can be divided in two parts, 2121 and 1212, that added together give a palindrome (3333).

The spelling of 21211212 in words is "twenty-one million, two hundred eleven thousand, two hundred twelve".

Divisors: 1 2 3 4 6 11 12 22 33 37 43 44 66 74 86 101 111 129 132 148 172 202 222 258 303 404 407 444 473 516 606 814 946 1111 1212 1221 1419 1591 1628 1892 2222 2442 2838 3182 3333 3737 4343 4444 4773 4884 5676 6364 6666 7474 8686 9546 11211 13029 13332 14948 17372 17501 19092 22422 26058 35002 41107 44844 47773 52116 52503 70004 82214 95546 105006 123321 143319 160691 164428 191092 210012 246642 286638 321382 482073 493284 573276 642764 964146 1767601 1928292 3535202 5302803 7070404 10605606 21211212