30720256 has 108 divisors (see below), whose sum is σ = 74565120. Its totient is φ = 12579840.

The previous prime is 30720247. The next prime is 30720259. The reversal of 30720256 is 65202703.

It is a self number, because there is not a number n which added to its sum of digits gives 30720256.

It is not an unprimeable number, because it can be changed into a prime (30720259) 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, 388825 + ... + 388903.

Almost surely, 2^30720256 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 30720256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37282560).

30720256 is an abundant number, since it is smaller than the sum of its proper divisors (43844864).

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

30720256 is an equidigital number, since it uses as much as digits as its factorization.

30720256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140 (or 119 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 25.

The square root of 30720256 is about 5542.5856781831. The cubic root of 30720256 is about 313.1902812617.

Adding to 30720256 its reverse (65202703), we get a palindrome (95922959).

It can be divided in two parts, 30720 and 256, that added together give a square (30976 = 176²).

The spelling of 30720256 in words is "thirty million, seven hundred twenty thousand, two hundred fifty-six".