Base | Representation |
---|---|
bin | 10011101111101100… |
… | …001111000110110101 |
3 | 2000201112211120100011 |
4 | 103233230033012311 |
5 | 321410003020041 |
6 | 13423435420221 |
7 | 1350246253042 |
oct | 235754170665 |
9 | 60645746304 |
10 | 21201220021 |
11 | 8a9a599443 |
12 | 41382b4671 |
13 | 1ccb508507 |
14 | 1051a521c9 |
15 | 841447e81 |
hex | 4efb0f1b5 |
21201220021 has 4 divisors (see below), whose sum is σ = 21201799852. Its totient is φ = 21200640192.
The previous prime is 21201219997. The next prime is 21201220031. The reversal of 21201220021 is 12002210212.
It is a happy number.
It is a semiprime because it is the product of two primes.
It can be written as a sum of positive squares in 2 ways, for example, as 6986619396 + 14214600625 = 83586^2 + 119225^2 .
It is a cyclic number.
It is not a de Polignac number, because 21201220021 - 221 = 21199122869 is a prime.
It is a Duffinian number.
It is a junction number, because it is equal to n+sod(n) for n = 21201219983 and 21201220010.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (21201220031) by changing a digit.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 231090 + ... + 309523.
It is an arithmetic number, because the mean of its divisors is an integer number (5300449963).
Almost surely, 221201220021 is an apocalyptic number.
It is an amenable number.
21201220021 is a deficient number, since it is larger than the sum of its proper divisors (579831).
21201220021 is an equidigital number, since it uses as much as digits as its factorization.
21201220021 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 579830.
The product of its (nonzero) digits is 32, while the sum is 13.
Adding to 21201220021 its reverse (12002210212), we get a palindrome (33203430233).
The spelling of 21201220021 in words is "twenty-one billion, two hundred one million, two hundred twenty thousand, twenty-one".
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