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10981 = 79139
BaseRepresentation
bin10101011100101
3120001201
42223211
5322411
6122501
744005
oct25345
916051
1010981
118283
126431
134cc9
144005
1533c1
hex2ae5

10981 has 4 divisors (see below), whose sum is σ = 11200. Its totient is φ = 10764.

The previous prime is 10979. The next prime is 10987. The reversal of 10981 is 18901.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18901 = 41461.

It is a cyclic number.

It is not a de Polignac number, because 10981 - 21 = 10979 is a prime.

It is a super-2 number, since 2×109812 = 241164722, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10987) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10 + ... + 148.

It is an arithmetic number, because the mean of its divisors is an integer number (2800).

210981 is an apocalyptic number.

10981 is the 61-st hex number.

It is an amenable number.

10981 is a deficient number, since it is larger than the sum of its proper divisors (219).

10981 is an equidigital number, since it uses as much as digits as its factorization.

10981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218.

The product of its (nonzero) digits is 72, while the sum is 19.

The square root of 10981 is about 104.7902667236. The cubic root of 10981 is about 22.2269887923.

It can be divided in two parts, 109 and 81, that added together give a triangular number (190 = T19).

The spelling of 10981 in words is "ten thousand, nine hundred eighty-one".

Divisors: 1 79 139 10981