28721604 has 12 divisors (see below), whose sum is σ = 67017104. Its totient is φ = 9573864.

The previous prime is 28721599. The next prime is 28721611. The reversal of 28721604 is 40612782.

It is a tau number, because it is divible by the number of its divisors (12).

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 1196722 + ... + 1196745.

Almost surely, 2^28721604 is an apocalyptic number.

It is an amenable number.

28721604 is an abundant number, since it is smaller than the sum of its proper divisors (38295500).

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

28721604 is a wasteful number, since it uses less digits than its factorization.

28721604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2393474 (or 2393472 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 30.

The square root of 28721604 is about 5359.2540525711. The cubic root of 28721604 is about 306.2453924616.

The spelling of 28721604 in words is "twenty-eight million, seven hundred twenty-one thousand, six hundred four".