28781533 has 8 divisors (see below), whose sum is σ = 32763456. Its totient is φ = 25027200.

The previous prime is 28781509. The next prime is 28781537. The reversal of 28781533 is 33518782.

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

It is a de Polignac number, because none of the positive numbers 2^k-28781533 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 28781492 and 28781501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28781537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56628 + ... + 57133.

It is an arithmetic number, because the mean of its divisors is an integer number (4095432).

Almost surely, 2^28781533 is an apocalyptic number.

28781533 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

28781533 is a deficient number, since it is larger than the sum of its proper divisors (3981923).

28781533 is a wasteful number, since it uses less digits than its factorization.

28781533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113795.

The product of its digits is 40320, while the sum is 37.

The square root of 28781533 is about 5364.8423089593. The cubic root of 28781533 is about 306.4582430404.

The spelling of 28781533 in words is "twenty-eight million, seven hundred eighty-one thousand, five hundred thirty-three".