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30920 = 235773
BaseRepresentation
bin111100011001000
31120102012
413203020
51442140
6355052
7156101
oct74310
946365
1030920
112125a
1215a88
13110c6
14b3a8
159265
hex78c8

30920 has 16 divisors (see below), whose sum is σ = 69660. Its totient is φ = 12352.

The previous prime is 30911. The next prime is 30931. The reversal of 30920 is 2903.

30920 = T54 + T55 + ... + T69.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 27556 + 3364 = 166^2 + 58^2 .

It is a nialpdrome in base 8.

It is a junction number, because it is equal to n+sod(n) for n = 30895 and 30904.

It is an unprimeable number.

30920 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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, 347 + ... + 426.

230920 is an apocalyptic number.

It is an amenable number.

30920 is an abundant number, since it is smaller than the sum of its proper divisors (38740).

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 (34830).

30920 is a wasteful number, since it uses less digits than its factorization.

30920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 784 (or 780 counting only the distinct ones).

The product of its (nonzero) digits is 54, while the sum is 14.

The square root of 30920 is about 175.8408371227. The cubic root of 30920 is about 31.3867606160.

The spelling of 30920 in words is "thirty thousand, nine hundred twenty".

Divisors: 1 2 4 5 8 10 20 40 773 1546 3092 3865 6184 7730 15460 30920