28721335 has 4 divisors (see below), whose sum is σ = 34465608. Its totient is φ = 22977064.

The previous prime is 28721333. The next prime is 28721351. The reversal of 28721335 is 53312782.

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 28721335 - 2¹ = 28721333 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28721297 and 28721306.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28721333) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2872129 + ... + 2872138.

It is an arithmetic number, because the mean of its divisors is an integer number (8616402).

Almost surely, 2^28721335 is an apocalyptic number.

28721335 is a deficient number, since it is larger than the sum of its proper divisors (5744273).

28721335 is an equidigital number, since it uses as much as digits as its factorization.

28721335 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5744272.

The product of its digits is 10080, while the sum is 31.

The square root of 28721335 is about 5359.2289557361. The cubic root of 28721335 is about 306.2444363837.

The spelling of 28721335 in words is "twenty-eight million, seven hundred twenty-one thousand, three hundred thirty-five".