28909438 has 4 divisors (see below), whose sum is σ = 43364160. Its totient is φ = 14454718.

The previous prime is 28909409. The next prime is 28909451. The reversal of 28909438 is 83490982.

It is a happy number.

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

It is a junction number, because it is equal to n+sod(n) for n = 28909394 and 28909403.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7227358 + ... + 7227361.

It is an arithmetic number, because the mean of its divisors is an integer number (10841040).

Almost surely, 2^28909438 is an apocalyptic number.

28909438 is a deficient number, since it is larger than the sum of its proper divisors (14454722).

28909438 is a wasteful number, since it uses less digits than its factorization.

28909438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14454721.

The product of its (nonzero) digits is 124416, while the sum is 43.

The square root of 28909438 is about 5376.7497617055. The cubic root of 28909438 is about 306.9115385609.

The spelling of 28909438 in words is "twenty-eight million, nine hundred nine thousand, four hundred thirty-eight".