28239431 has 8 divisors (see below), whose sum is σ = 32619024. Its totient is φ = 24161920.

The previous prime is 28239427. The next prime is 28239437. The reversal of 28239431 is 13493282.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28239431 - 2² = 28239427 is a prime.

It is a super-2 number, since 2×28239431² = 1594930926407522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28239437) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75320 + ... + 75693.

It is an arithmetic number, because the mean of its divisors is an integer number (4077378).

Almost surely, 2^28239431 is an apocalyptic number.

28239431 is a deficient number, since it is larger than the sum of its proper divisors (4379593).

28239431 is a wasteful number, since it uses less digits than its factorization.

28239431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151041.

The product of its digits is 10368, while the sum is 32.

The square root of 28239431 is about 5314.0785654712. The cubic root of 28239431 is about 304.5219816548.

The spelling of 28239431 in words is "twenty-eight million, two hundred thirty-nine thousand, four hundred thirty-one".