Base | Representation |
---|---|
bin | 111100011110110111001 |
3 | 10201200122000 |
4 | 13203312321 |
5 | 1001410011 |
6 | 110251213 |
7 | 22563036 |
oct | 7436671 |
9 | 3650560 |
10 | 1981881 |
11 | 1134020 |
12 | 7b6b09 |
13 | 545115 |
14 | 39838d |
15 | 292356 |
hex | 1e3db9 |
1981881 has 16 divisors (see below), whose sum is σ = 3203520. Its totient is φ = 1200960.
The previous prime is 1981879. The next prime is 1981883. The reversal of 1981881 is 1881891.
It is an interprime number because it is at equal distance from previous prime (1981879) and next prime (1981883).
It is not a de Polignac number, because 1981881 - 21 = 1981879 is a prime.
It is a super-2 number, since 2×19818812 = 7855704596322, which contains 22 as substring.
It is a Curzon number.
It is not an unprimeable number, because it can be changed into a prime (1981883) 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, 3040 + ... + 3633.
It is an arithmetic number, because the mean of its divisors is an integer number (200220).
21981881 is an apocalyptic number.
1981881 is a gapful number since it is divisible by the number (11) formed by its first and last digit.
It is an amenable number.
1981881 is a deficient number, since it is larger than the sum of its proper divisors (1221639).
1981881 is a wasteful number, since it uses less digits than its factorization.
1981881 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 6693 (or 6687 counting only the distinct ones).
The product of its digits is 4608, while the sum is 36.
The square root of 1981881 is about 1407.7929535269. The cubic root of 1981881 is about 125.6104750415.
The spelling of 1981881 in words is "one million, nine hundred eighty-one thousand, eight hundred eighty-one".
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