Base | Representation |
---|---|
bin | 101000000100… |
… | …1111000110101 |
3 | 1110112112002000 |
4 | 1100021320311 |
5 | 20334341041 |
6 | 2030205513 |
7 | 343412352 |
oct | 120117065 |
9 | 43475060 |
10 | 21012021 |
11 | 10951708 |
12 | 7053899 |
13 | 4478c64 |
14 | 2b0d629 |
15 | 1ca0bb6 |
hex | 1409e35 |
21012021 has 8 divisors (see below), whose sum is σ = 31128960. Its totient is φ = 14007996.
The previous prime is 21011981. The next prime is 21012053. The reversal of 21012021 is 12021012.
It is not a de Polignac number, because 21012021 - 26 = 21011957 is a prime.
It is a Harshad number since it is a multiple of its sum of digits (9).
It is a junction number, because it is equal to n+sod(n) for n = 21011994 and 21012012.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (21012091) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (11) of ones.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 389085 + ... + 389138.
It is an arithmetic number, because the mean of its divisors is an integer number (3891120).
Almost surely, 221012021 is an apocalyptic number.
It is an amenable number.
21012021 is a deficient number, since it is larger than the sum of its proper divisors (10116939).
21012021 is an equidigital number, since it uses as much as digits as its factorization.
21012021 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 778232 (or 778226 counting only the distinct ones).
The product of its (nonzero) digits is 8, while the sum is 9.
The square root of 21012021 is about 4583.8871059397. The cubic root of 21012021 is about 275.9450504974.
Adding to 21012021 its reverse (12021012), we get a palindrome (33033033).
The spelling of 21012021 in words is "twenty-one million, twelve thousand, twenty-one".
• e-mail: info -at- numbersaplenty.com • Privacy notice • done in 0.069 sec. • engine limits •