Base | Representation |
---|---|
bin | 101000011101… |
… | …0100001001100 |
3 | 1110220122022110 |
4 | 1100322201030 |
5 | 20412224322 |
6 | 2034344020 |
7 | 345202161 |
oct | 120724114 |
9 | 43818273 |
10 | 21211212 |
11 | 10a78330 |
12 | 712b010 |
13 | 4518819 |
14 | 2b62068 |
15 | 1cdec0c |
hex | 143a84c |
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".
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