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BaseRepresentation
bin10011011000
31200221
4103120
514430
65424
73421
oct2330
91627
101240
11a28
12874
13745
14648
1557a
hex4d8

1240 has 16 divisors (see below), whose sum is σ = 2880. Its totient is φ = 480.

The previous prime is 1237. The next prime is 1249. The reversal of 1240 is 421.

1240 = 12 + 22 + ... + 152.

It is a plaindrome in base 15.

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 (1249) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25 + ... + 55.

It is an arithmetic number, because the mean of its divisors is an integer number (180).

21240 is an apocalyptic number.

1240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1440).

1240 is an abundant number, since it is smaller than the sum of its proper divisors (1640).

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

1240 is a wasteful number, since it uses less digits than its factorization.

1240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42 (or 38 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 7.

The square root of 1240 is about 35.2136337233. The cubic root of 1240 is about 10.7433707099.

Adding to 1240 its reverse (421), we get a palindrome (1661).

The spelling of 1240 in words is "one thousand, two hundred forty", and thus it is an iban number.

Divisors: 1 2 4 5 8 10 20 31 40 62 124 155 248 310 620 1240