28239501 has 4 divisors (see below), whose sum is σ = 37652672. Its totient is φ = 18826332.

The previous prime is 28239487. The next prime is 28239509. The reversal of 28239501 is 10593282.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 28239501 - 2⁶ = 28239437 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28239509) 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, 4706581 + ... + 4706586.

It is an arithmetic number, because the mean of its divisors is an integer number (9413168).

Almost surely, 2^28239501 is an apocalyptic number.

It is an amenable number.

28239501 is a deficient number, since it is larger than the sum of its proper divisors (9413171).

28239501 is an equidigital number, since it uses as much as digits as its factorization.

28239501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9413170.

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 28239501 is about 5314.0851517453. The cubic root of 28239501 is about 304.5222332713.

The spelling of 28239501 in words is "twenty-eight million, two hundred thirty-nine thousand, five hundred one".