28721567 has 8 divisors (see below), whose sum is σ = 32860800. Its totient is φ = 24591384.

The previous prime is 28721557. The next prime is 28721573. The reversal of 28721567 is 76512782.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28721567 - 2⁸ = 28721311 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28721567.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28721527) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7184 + ... + 10442.

It is an arithmetic number, because the mean of its divisors is an integer number (4107600).

Almost surely, 2^28721567 is an apocalyptic number.

28721567 is a deficient number, since it is larger than the sum of its proper divisors (4139233).

28721567 is a wasteful number, since it uses less digits than its factorization.

28721567 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4525.

The product of its digits is 47040, while the sum is 38.

The square root of 28721567 is about 5359.2506005971. The cubic root of 28721567 is about 306.2452609568.

The spelling of 28721567 in words is "twenty-eight million, seven hundred twenty-one thousand, five hundred sixty-seven".