28440947 has 4 divisors (see below), whose sum is σ = 28451616. Its totient is φ = 28430280.

The previous prime is 28440943. The next prime is 28440961. The reversal of 28440947 is 74904482.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 28440947 - 2² = 28440943 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 28440947.

It is not an unprimeable number, because it can be changed into a prime (28440941) 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, 2513 + ... + 7949.

It is an arithmetic number, because the mean of its divisors is an integer number (7112904).

Almost surely, 2^28440947 is an apocalyptic number.

28440947 is a deficient number, since it is larger than the sum of its proper divisors (10669).

28440947 is an equidigital number, since it uses as much as digits as its factorization.

28440947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10668.

The product of its (nonzero) digits is 64512, while the sum is 38.

The square root of 28440947 is about 5333.0054378371. The cubic root of 28440947 is about 305.2446196645.

The spelling of 28440947 in words is "twenty-eight million, four hundred forty thousand, nine hundred forty-seven".