28399139 has 4 divisors (see below), whose sum is σ = 29003424. Its totient is φ = 27794856.

The previous prime is 28399121. The next prime is 28399153. The reversal of 28399139 is 93199382.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93199382 = 2 ⋅46599691.

It is a cyclic number.

It is not a de Polignac number, because 28399139 - 2²⁰ = 27350563 is a prime.

It is a super-2 number, since 2×28399139² = 1613022191882642, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28399139.

It is not an unprimeable number, because it can be changed into a prime (28399109) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 302072 + ... + 302165.

It is an arithmetic number, because the mean of its divisors is an integer number (7250856).

Almost surely, 2^28399139 is an apocalyptic number.

28399139 is a deficient number, since it is larger than the sum of its proper divisors (604285).

28399139 is an equidigital number, since it uses as much as digits as its factorization.

28399139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 604284.

The product of its digits is 104976, while the sum is 44.

The square root of 28399139 is about 5329.0842552919. The cubic root of 28399139 is about 305.0949771396.

The spelling of 28399139 in words is "twenty-eight million, three hundred ninety-nine thousand, one hundred thirty-nine".