28388923 has 8 divisors (see below), whose sum is σ = 29700000. Its totient is φ = 27084288.

The previous prime is 28388909. The next prime is 28388947. The reversal of 28388923 is 32988382.

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 28388923 - 2⁹ = 28388411 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28388923.

It is not an unprimeable number, because it can be changed into a prime (28388023) 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, 8953 + ... + 11701.

It is an arithmetic number, because the mean of its divisors is an integer number (3712500).

Almost surely, 2^28388923 is an apocalyptic number.

28388923 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

28388923 is a deficient number, since it is larger than the sum of its proper divisors (1311077).

28388923 is a wasteful number, since it uses less digits than its factorization.

28388923 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3221.

The product of its digits is 165888, while the sum is 43.

The square root of 28388923 is about 5328.1256554252. The cubic root of 28388923 is about 305.0583888930.

The spelling of 28388923 in words is "twenty-eight million, three hundred eighty-eight thousand, nine hundred twenty-three".