Base | Representation |
---|---|
bin | 101000101001… |
… | …1001100000001 |
3 | 1111002202220212 |
4 | 1101103030001 |
5 | 20423443012 |
6 | 2040443505 |
7 | 346102601 |
oct | 121231401 |
9 | 44082825 |
10 | 21312257 |
11 | 1103723a |
12 | 7179595 |
13 | 4552805 |
14 | 2b8ac01 |
15 | 1d0eb22 |
hex | 1453301 |
21312257 has 2 divisors, whose sum is σ = 21312258. Its totient is φ = 21312256.
The previous prime is 21312233. The next prime is 21312289. The reversal of 21312257 is 75221312.
It is a happy number.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 17505856 + 3806401 = 4184^2 + 1951^2 .
It is a cyclic number.
It is not a de Polignac number, because 21312257 - 28 = 21312001 is a prime.
It is not a weakly prime, because it can be changed into another prime (21312457) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656128 + 10656129.
It is an arithmetic number, because the mean of its divisors is an integer number (10656129).
Almost surely, 221312257 is an apocalyptic number.
It is an amenable number.
21312257 is a deficient number, since it is larger than the sum of its proper divisors (1).
21312257 is an equidigital number, since it uses as much as digits as its factorization.
21312257 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 840, while the sum is 23.
The square root of 21312257 is about 4616.5200097043. The cubic root of 21312257 is about 277.2531451873.
Adding to 21312257 its reverse (75221312), we get a palindrome (96533569).
The spelling of 21312257 in words is "twenty-one million, three hundred twelve thousand, two hundred fifty-seven".
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