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2981 = 11271
BaseRepresentation
bin101110100101
311002102
4232211
543411
621445
711456
oct5645
94072
102981
112270
121885
131484
14112d
15d3b
hexba5

2981 has 4 divisors (see below), whose sum is σ = 3264. Its totient is φ = 2700.

The previous prime is 2971. The next prime is 2999. The reversal of 2981 is 1892.

Adding to 2981 its product of digits (144), we get a 5-th power (3125 = 55).

Subtracting from 2981 its reverse (1892), we obtain a square (1089 = 332).

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.

It is a cyclic number.

It is not a de Polignac number, because 2981 - 26 = 2917 is a prime.

It is a super-2 number, since 2×29812 = 17772722, which contains 22 as substring.

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

It is a deceptive number, since it divides R2980.

It is a Duffinian number.

It is a plaindrome in base 7 and base 14.

It is a nialpdrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 125 + ... + 146.

It is an arithmetic number, because the mean of its divisors is an integer number (816).

22981 is an apocalyptic number.

It is an amenable number.

2981 is a deficient number, since it is larger than the sum of its proper divisors (283).

2981 is a wasteful number, since it uses less digits than its factorization.

2981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 282.

The product of its digits is 144, while the sum is 20.

The square root of 2981 is about 54.5985347789. The cubic root of 2981 is about 14.3919837070.

The spelling of 2981 in words is "two thousand, nine hundred eighty-one".

Divisors: 1 11 271 2981