30728520 has 96 divisors (see below), whose sum is σ = 105763320. Its totient is φ = 7710720.

The previous prime is 30728497. The next prime is 30728521. The reversal of 30728520 is 2582703.

It can be written as a sum of positive squares in 4 ways, for example, as 30536676 + 191844 = 5526^2 + 438^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30728521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3610 + ... + 8630.

Almost surely, 2^30728520 is an apocalyptic number.

30728520 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 30728520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (52881660).

30728520 is an abundant number, since it is smaller than the sum of its proper divisors (75034800).

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

30728520 is a wasteful number, since it uses less digits than its factorization.

30728520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5055 (or 5048 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 30728520 is about 5543.3311284822. The cubic root of 30728520 is about 313.2183623258.

The spelling of 30728520 in words is "thirty million, seven hundred twenty-eight thousand, five hundred twenty".