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BaseRepresentation
bin101011011100
310210222
4223130
542110
620512
711051
oct5334
93728
102780
1120a8
121738
13135b
141028
15c55

2780 has 12 divisors (see below), whose sum is σ = 5880. Its totient is φ = 1104.

The previous prime is 2777. The next prime is 2789. The reversal of 2780 is 872.

2780 = 152 + 162 + ... + 222.

It is a plaindrome in base 13.

It is a nialpdrome in base 5 and base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2789) 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, 50 + ... + 89.

It is an arithmetic number, because the mean of its divisors is an integer number (490).

22780 is an apocalyptic number.

2780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2780 is an abundant number, since it is smaller than the sum of its proper divisors (3100).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2940).

2780 is a wasteful number, since it uses less digits than its factorization.

2780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 148 (or 146 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 17.

The square root of 2780 is about 52.7257053059. The cubic root of 2780 is about 14.0609586788.

The spelling of 2780 in words is "two thousand, seven hundred eighty".

Divisors: 1 2 4 5 10 20 139 278 556 695 1390 2780