30820 has 24 divisors (see below), whose sum is σ = 68544. Its totient is φ = 11616.

The previous prime is 30817. The next prime is 30829. The reversal of 30820 is 2803.

30820 = 25² + 26² + ... + 47².

It is a plaindrome in base 7.

It is a self number, because there is not a number n which added to its sum of digits gives 30820.

It is not an unprimeable number, because it can be changed into a prime (30829) 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 7 ways as a sum of consecutive naturals, for example, 427 + ... + 493.

It is an arithmetic number, because the mean of its divisors is an integer number (2856).

2³⁰⁸²⁰ 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 30820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34272).

30820 is an abundant number, since it is smaller than the sum of its proper divisors (37724).

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

30820 is a wasteful number, since it uses less digits than its factorization.

30820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99 (or 97 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 30820 is about 175.5562587890. The cubic root of 30820 is about 31.3528875478.

The spelling of 30820 in words is "thirty thousand, eight hundred twenty".