Base | Representation |
---|---|
bin | 101001000010… |
… | …1111011111001 |
3 | 1111111100001112 |
4 | 1102011323321 |
5 | 21002120441 |
6 | 2045130105 |
7 | 350626610 |
oct | 122057371 |
9 | 44440045 |
10 | 21520121 |
11 | 11169427 |
12 | 7259935 |
13 | 45c62cc |
14 | 2c02877 |
15 | 1d514eb |
hex | 1485ef9 |
21520121 has 16 divisors (see below), whose sum is σ = 25401600. Its totient is φ = 17848320.
The previous prime is 21520091. The next prime is 21520133. The reversal of 21520121 is 12102512.
It is not a de Polignac number, because 21520121 - 214 = 21503737 is a prime.
It is a junction number, because it is equal to n+sod(n) for n = 21520096 and 21520105.
It is not an unprimeable number, because it can be changed into a prime (21520151) by changing a digit.
It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47705 + ... + 48153.
It is an arithmetic number, because the mean of its divisors is an integer number (1587600).
Almost surely, 221520121 is an apocalyptic number.
It is an amenable number.
21520121 is a deficient number, since it is larger than the sum of its proper divisors (3881479).
21520121 is a wasteful number, since it uses less digits than its factorization.
21520121 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 664.
The product of its (nonzero) digits is 40, while the sum is 14.
The square root of 21520121 is about 4638.9784435800. The cubic root of 21520121 is about 278.1516045922.
Adding to 21520121 its reverse (12102512), we get a palindrome (33622633).
The spelling of 21520121 in words is "twenty-one million, five hundred twenty thousand, one hundred twenty-one".
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