30820720 has 80 divisors (see below), whose sum is σ = 83708928. Its totient is φ = 10333440.

The previous prime is 30820703. The next prime is 30820721. The reversal of 30820720 is 2702803.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 30820691 and 30820700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30820721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25735 + ... + 26905.

Almost surely, 2^30820720 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 30820720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41854464).

30820720 is an abundant number, since it is smaller than the sum of its proper divisors (52888208).

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

30820720 is a wasteful number, since it uses less digits than its factorization.

30820720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1238 (or 1232 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 30820720 is about 5551.6411987808. The cubic root of 30820720 is about 313.5313169556.

The spelling of 30820720 in words is "thirty million, eight hundred twenty thousand, seven hundred twenty".