28909723 has 4 divisors (see below), whose sum is σ = 29906640. Its totient is φ = 27912808.

The previous prime is 28909721. The next prime is 28909729. The reversal of 28909723 is 32790982.

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 28909723 - 2¹ = 28909721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28909721) 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, 498415 + ... + 498472.

It is an arithmetic number, because the mean of its divisors is an integer number (7476660).

Almost surely, 2^28909723 is an apocalyptic number.

28909723 is a deficient number, since it is larger than the sum of its proper divisors (996917).

28909723 is an equidigital number, since it uses as much as digits as its factorization.

28909723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 996916.

The product of its (nonzero) digits is 54432, while the sum is 40.

The square root of 28909723 is about 5376.7762646404. The cubic root of 28909723 is about 306.9125471070.

The spelling of 28909723 in words is "twenty-eight million, nine hundred nine thousand, seven hundred twenty-three".