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7920 = 2432511
BaseRepresentation
bin1111011110000
3101212100
41323300
5223140
6100400
732043
oct17360
911770
107920
115a50
124700
1337b3
142c5a
152530
hex1ef0

7920 has 60 divisors (see below), whose sum is σ = 29016. Its totient is φ = 1920.

The previous prime is 7919. The next prime is 7927. The reversal of 7920 is 297.

It can be divided in two parts, 79 and 20, that added together give a palindrome (99).

It is a Cunningham number, because it is equal to 892-1.

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 7893 and 7902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7927) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 715 + ... + 725.

27920 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 7920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14508).

7920 is an abundant number, since it is smaller than the sum of its proper divisors (21096).

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

7920 is a wasteful number, since it uses less digits than its factorization.

7920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30 (or 21 counting only the distinct ones).

The product of its (nonzero) digits is 126, while the sum is 18.

The square root of 7920 is about 88.9943818451. The cubic root of 7920 is about 19.9331098683.

The spelling of 7920 in words is "seven thousand, nine hundred twenty".

Divisors: 1 2 3 4 5 6 8 9 10 11 12 15 16 18 20 22 24 30 33 36 40 44 45 48 55 60 66 72 80 88 90 99 110 120 132 144 165 176 180 198 220 240 264 330 360 396 440 495 528 660 720 792 880 990 1320 1584 1980 2640 3960 7920