Base | Representation |
---|---|
bin | 101010101011011 |
3 | 1002222022 |
4 | 11111123 |
5 | 1144401 |
6 | 245055 |
7 | 120464 |
oct | 52533 |
9 | 32868 |
10 | 21851 |
11 | 15465 |
12 | 1078b |
13 | 9c3b |
14 | 7d6b |
15 | 671b |
hex | 555b |
21851 has 2 divisors, whose sum is σ = 21852. Its totient is φ = 21850.
The previous prime is 21841. The next prime is 21859. The reversal of 21851 is 15812.
It is a strong prime.
It is a cyclic number.
It is not a de Polignac number, because 21851 - 26 = 21787 is a prime.
It is a plaindrome in base 4 and base 16.
It is not a weakly prime, because it can be changed into another prime (21859) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10925 + 10926.
It is an arithmetic number, because the mean of its divisors is an integer number (10926).
221851 is an apocalyptic number.
21851 is a deficient number, since it is larger than the sum of its proper divisors (1).
21851 is an equidigital number, since it uses as much as digits as its factorization.
21851 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 80, while the sum is 17.
The square root of 21851 is about 147.8208375027. The cubic root of 21851 is about 27.9569917960.
It can be divided in two parts, 21 and 851, that multiplied together give a palindrome (17871).
The spelling of 21851 in words is "twenty-one thousand, eight hundred fifty-one".
• e-mail: info -at- numbersaplenty.com • Privacy notice • done in 0.074 sec. • engine limits •