| Base | Representation |
|---|---|
| bin | 10011101011000010… |
| … | …010110011101010100 |
| 3 | 2000112002220020122100 |
| 4 | 103223002112131110 |
| 5 | 321230010144340 |
| 6 | 13412010002100 |
| 7 | 1345310436642 |
| oct | 235302263524 |
| 9 | 60462806570 |
| 10 | 21123131220 |
| 11 | 8a5a503144 |
| 12 | 4116116330 |
| 13 | 1cb8297019 |
| 14 | 1045526192 |
| 15 | 839670830 |
| hex | 4eb096754 |
21123131220 has 36 divisors (see below), whose sum is σ = 64073498580. Its totient is φ = 5632834944.
The previous prime is 21123131203. The next prime is 21123131221. The reversal of 21123131220 is 2213132112.
21123131220 is a `hidden beast` number, since 211 + 231 + 3 + 1 + 220 = 666.
It can be written as a sum of positive squares in 2 ways, for example, as 9163084176 + 11960047044 = 95724^2 + 109362^2 .
It is a tau number, because it is divible by the number of its divisors (36).
It is a Harshad number since it is a multiple of its sum of digits (18).
It is a junction number, because it is equal to n+sod(n) for n = 21123131193 and 21123131202.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (21123131221) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (17) of ones.
It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 58675185 + ... + 58675544.
It is an arithmetic number, because the mean of its divisors is an integer number (1779819405).
Almost surely, 221123131220 is an apocalyptic number.
21123131220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.
It is an amenable number.
21123131220 is an abundant number, since it is smaller than the sum of its proper divisors (42950367360).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
21123131220 is a wasteful number, since it uses less digits than its factorization.
21123131220 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 117350744 (or 117350739 counting only the distinct ones).
The product of its (nonzero) digits is 144, while the sum is 18.
Adding to 21123131220 its reverse (2213132112), we get a palindrome (23336263332).
The spelling of 21123131220 in words is "twenty-one billion, one hundred twenty-three million, one hundred thirty-one thousand, two hundred twenty".
• e-mail: info -at- numbersaplenty.com • Privacy notice • done in 0.101 sec. • engine limits •