30728640 has 56 divisors (see below), whose sum is σ = 97566480. Its totient is φ = 8194048.

The previous prime is 30728629. The next prime is 30728641. The reversal of 30728640 is 4682703.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 30728598 and 30728607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30728641) 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 7 ways as a sum of consecutive naturals, for example, 15045 + ... + 16964.

Almost surely, 2^30728640 is an apocalyptic number.

30728640 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

30728640 is an abundant number, since it is smaller than the sum of its proper divisors (66837840).

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

30728640 is a wasteful number, since it uses less digits than its factorization.

30728640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32029 (or 32019 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 30.

The square root of 30728640 is about 5543.3419522883. The cubic root of 30728640 is about 313.2187700486.

The spelling of 30728640 in words is "thirty million, seven hundred twenty-eight thousand, six hundred forty".