28689993 has 12 divisors (see below), whose sum is σ = 43243200. Its totient is φ = 18294936.

The previous prime is 28689979. The next prime is 28690001. The reversal of 28689993 is 39998682.

It is not a de Polignac number, because 28689993 - 2⁸ = 28689737 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28689953) 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 11 ways as a sum of consecutive naturals, for example, 69093 + ... + 69506.

It is an arithmetic number, because the mean of its divisors is an integer number (3603600).

Almost surely, 2^28689993 is an apocalyptic number.

28689993 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

28689993 is a deficient number, since it is larger than the sum of its proper divisors (14553207).

28689993 is a wasteful number, since it uses less digits than its factorization.

28689993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138628 (or 138625 counting only the distinct ones).

The product of its digits is 1679616, while the sum is 54.

The square root of 28689993 is about 5356.3040429012. The cubic root of 28689993 is about 306.1329999827.

The spelling of 28689993 in words is "twenty-eight million, six hundred eighty-nine thousand, nine hundred ninety-three".