28129306 has 4 divisors (see below), whose sum is σ = 42193962. Its totient is φ = 14064652.

The previous prime is 28129301. The next prime is 28129393. The reversal of 28129306 is 60392182.

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

It can be written as a sum of positive squares in only one way, i.e., 22953681 + 5175625 = 4791^2 + 2275^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (28129301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7032325 + ... + 7032328.

Almost surely, 2^28129306 is an apocalyptic number.

28129306 is a deficient number, since it is larger than the sum of its proper divisors (14064656).

28129306 is a wasteful number, since it uses less digits than its factorization.

28129306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14064655.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 28129306 is about 5303.7068169347. The cubic root of 28129306 is about 304.1256189640.

The spelling of 28129306 in words is "twenty-eight million, one hundred twenty-nine thousand, three hundred six".