28308447 has 20 divisors (see below), whose sum is σ = 42613296. Its totient is φ = 18727200.

The previous prime is 28308443. The next prime is 28308457. The reversal of 28308447 is 74480382.

It is not a de Polignac number, because 28308447 - 2² = 28308443 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28308443) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 9822 + ... + 12372.

Almost surely, 2^28308447 is an apocalyptic number.

28308447 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

28308447 is a deficient number, since it is larger than the sum of its proper divisors (14304849).

28308447 is a wasteful number, since it uses less digits than its factorization.

28308447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2700 (or 2691 counting only the distinct ones).

The product of its (nonzero) digits is 43008, while the sum is 36.

The square root of 28308447 is about 5320.5682967142. The cubic root of 28308447 is about 304.7698595344.

The spelling of 28308447 in words is "twenty-eight million, three hundred eight thousand, four hundred forty-seven".