28251947 has 4 divisors (see below), whose sum is σ = 28291536. Its totient is φ = 28212360.

The previous prime is 28251907. The next prime is 28251953. The reversal of 28251947 is 74915282.

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 28251947 - 2²⁴ = 11474731 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28251947.

It is not an unprimeable number, because it can be changed into a prime (28251907) 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, 18704 + ... + 20157.

It is an arithmetic number, because the mean of its divisors is an integer number (7072884).

Almost surely, 2^28251947 is an apocalyptic number.

28251947 is a deficient number, since it is larger than the sum of its proper divisors (39589).

28251947 is an equidigital number, since it uses as much as digits as its factorization.

28251947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39588.

The product of its digits is 40320, while the sum is 38.

The square root of 28251947 is about 5315.2560615647. The cubic root of 28251947 is about 304.5669640788.

The spelling of 28251947 in words is "twenty-eight million, two hundred fifty-one thousand, nine hundred forty-seven".