28943239 has 4 divisors (see below), whose sum is σ = 31169656. Its totient is φ = 26716824.

The previous prime is 28943237. The next prime is 28943249. The reversal of 28943239 is 93234982.

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

It is a cyclic number.

It is not a de Polignac number, because 28943239 - 2¹ = 28943237 is a prime.

It is a super-2 number, since 2×28943239² = 1675422167622242, 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 (28943237) 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, 1113189 + ... + 1113214.

It is an arithmetic number, because the mean of its divisors is an integer number (7792414).

Almost surely, 2^28943239 is an apocalyptic number.

28943239 is a deficient number, since it is larger than the sum of its proper divisors (2226417).

28943239 is a wasteful number, since it uses less digits than its factorization.

28943239 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2226416.

The product of its digits is 93312, while the sum is 40.

The square root of 28943239 is about 5379.8920992897. The cubic root of 28943239 is about 307.0311059316.

The spelling of 28943239 in words is "twenty-eight million, nine hundred forty-three thousand, two hundred thirty-nine".