28688551 has 4 divisors (see below), whose sum is σ = 28706112. Its totient is φ = 28670992.

The previous prime is 28688533. The next prime is 28688557. The reversal of 28688551 is 15588682.

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 28688551 - 2¹³ = 28680359 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28688498 and 28688507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28688557) 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, 6046 + ... + 9691.

It is an arithmetic number, because the mean of its divisors is an integer number (7176528).

Almost surely, 2^28688551 is an apocalyptic number.

28688551 is a deficient number, since it is larger than the sum of its proper divisors (17561).

28688551 is a wasteful number, since it uses less digits than its factorization.

28688551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17560.

The product of its digits is 153600, while the sum is 43.

The square root of 28688551 is about 5356.1694334664. The cubic root of 28688551 is about 306.1278710030.

The spelling of 28688551 in words is "twenty-eight million, six hundred eighty-eight thousand, five hundred fifty-one".