28399239 has 24 divisors (see below), whose sum is σ = 45965712. Its totient is φ = 16744320.

The previous prime is 28399213. The next prime is 28399249. The reversal of 28399239 is 93299382.

28399239 is a `hidden beast` number, since 28 + 399 + 239 = 666.

It is not a de Polignac number, because 28399239 - 2¹⁶ = 28333703 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 28399194 and 28399203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28399249) 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 23 ways as a sum of consecutive naturals, for example, 214 + ... + 7539.

It is an arithmetic number, because the mean of its divisors is an integer number (1915238).

Almost surely, 2^28399239 is an apocalyptic number.

28399239 is a deficient number, since it is larger than the sum of its proper divisors (17566473).

28399239 is a wasteful number, since it uses less digits than its factorization.

28399239 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7807 (or 7804 counting only the distinct ones).

The product of its digits is 209952, while the sum is 45.

The square root of 28399239 is about 5329.0936377587. The cubic root of 28399239 is about 305.0953352428.

The spelling of 28399239 in words is "twenty-eight million, three hundred ninety-nine thousand, two hundred thirty-nine".