28448139 has 4 divisors (see below), whose sum is σ = 37930856. Its totient is φ = 18965424.

The previous prime is 28448129. The next prime is 28448141. The reversal of 28448139 is 93184482.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 28448139 - 2⁵ = 28448107 is a prime.

It is a super-2 number, since 2×28448139² = 1618593225126642, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28448097 and 28448106.

It is not an unprimeable number, because it can be changed into a prime (28448129) 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, 4741354 + ... + 4741359.

It is an arithmetic number, because the mean of its divisors is an integer number (9482714).

Almost surely, 2^28448139 is an apocalyptic number.

28448139 is a deficient number, since it is larger than the sum of its proper divisors (9482717).

28448139 is an equidigital number, since it uses as much as digits as its factorization.

28448139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9482716.

The product of its digits is 55296, while the sum is 39.

The square root of 28448139 is about 5333.6796866704. The cubic root of 28448139 is about 305.2703470578.

The spelling of 28448139 in words is "twenty-eight million, four hundred forty-eight thousand, one hundred thirty-nine".