28929389 has 4 divisors (see below), whose sum is σ = 29325756. Its totient is φ = 28533024.

The previous prime is 28929379. The next prime is 28929391. The reversal of 28929389 is 98392982.

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

It can be written as a sum of positive squares in 2 ways, for example, as 21949225 + 6980164 = 4685^2 + 2642^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28929389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28929319) 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, 198074 + ... + 198219.

It is an arithmetic number, because the mean of its divisors is an integer number (7331439).

Almost surely, 2^28929389 is an apocalyptic number.

It is an amenable number.

28929389 is a deficient number, since it is larger than the sum of its proper divisors (396367).

28929389 is an equidigital number, since it uses as much as digits as its factorization.

28929389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 396366.

The product of its digits is 559872, while the sum is 50.

The square root of 28929389 is about 5378.6047447270. The cubic root of 28929389 is about 306.9821243221.

The spelling of 28929389 in words is "twenty-eight million, nine hundred twenty-nine thousand, three hundred eighty-nine".