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13881 = 37661
BaseRepresentation
bin11011000111001
3201001010
43120321
5421011
6144133
755320
oct33071
921033
1013881
11a47a
128049
13641a
1450b7
1541a6
hex3639

13881 has 8 divisors (see below), whose sum is σ = 21184. Its totient is φ = 7920.

The previous prime is 13879. The next prime is 13883. The reversal of 13881 is 18831.

Subtracting from 13881 its product of digits (192), we obtain a square (13689 = 1172).

Subtracting 13881 from its reverse (18831), we obtain a triangular number (4950 = T99).

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (13879) and next prime (13883).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 13881 - 21 = 13879 is a prime.

It is a super-2 number, since 2×138812 = 385364322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 661 = 13881 / (1 + 3 + 8 + 8 + 1).

It is a Duffinian number.

It is a Curzon number.

It is a nialpdrome in base 7.

It is not an unprimeable number, because it can be changed into a prime (13883) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 310 + ... + 351.

It is an arithmetic number, because the mean of its divisors is an integer number (2648).

213881 is an apocalyptic number.

It is an amenable number.

13881 is a deficient number, since it is larger than the sum of its proper divisors (7303).

13881 is an equidigital number, since it uses as much as digits as its factorization.

13881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 671.

The product of its digits is 192, while the sum is 21.

The square root of 13881 is about 117.8176557227. The cubic root of 13881 is about 24.0329408779.

The spelling of 13881 in words is "thirteen thousand, eight hundred eighty-one".

Divisors: 1 3 7 21 661 1983 4627 13881