28405247 has 8 divisors (see below), whose sum is σ = 32200560. Its totient is φ = 24840000.

The previous prime is 28405243. The next prime is 28405259. The reversal of 28405247 is 74250482.

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 28405247 - 2² = 28405243 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 (28405243) 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, 57254 + ... + 57747.

It is an arithmetic number, because the mean of its divisors is an integer number (4025070).

Almost surely, 2^28405247 is an apocalyptic number.

28405247 is a deficient number, since it is larger than the sum of its proper divisors (3795313).

28405247 is a wasteful number, since it uses less digits than its factorization.

28405247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115033.

The product of its (nonzero) digits is 17920, while the sum is 32.

The square root of 28405247 is about 5329.6573060564. The cubic root of 28405247 is about 305.1168485367.

The spelling of 28405247 in words is "twenty-eight million, four hundred five thousand, two hundred forty-seven".