30728591 has 4 divisors (see below), whose sum is σ = 30949800. Its totient is φ = 30507384.

The previous prime is 30728573. The next prime is 30728623. The reversal of 30728591 is 19582703.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 30728591 - 2⁶ = 30728527 is a prime.

It is a Duffinian number.

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 polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 110396 + ... + 110673.

It is an arithmetic number, because the mean of its divisors is an integer number (7737450).

Almost surely, 2^30728591 is an apocalyptic number.

30728591 is a deficient number, since it is larger than the sum of its proper divisors (221209).

30728591 is a wasteful number, since it uses less digits than its factorization.

30728591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221208.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 30728591 is about 5543.3375325701. The cubic root of 30728591 is about 313.2186035619.

The spelling of 30728591 in words is "thirty million, seven hundred twenty-eight thousand, five hundred ninety-one".