28447081 has 4 divisors (see below), whose sum is σ = 30635332. Its totient is φ = 26258832.

The previous prime is 28447063. The next prime is 28447157. The reversal of 28447081 is 18074482.

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

It can be written as a sum of positive squares in 2 ways, for example, as 16475481 + 11971600 = 4059^2 + 3460^2 .

It is a cyclic number.

It is not a de Polignac number, because 28447081 - 2⁵ = 28447049 is a prime.

It is a super-2 number, since 2×28447081² = 1618472834841122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28447051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1094106 + ... + 1094131.

It is an arithmetic number, because the mean of its divisors is an integer number (7658833).

Almost surely, 2^28447081 is an apocalyptic number.

It is an amenable number.

28447081 is a deficient number, since it is larger than the sum of its proper divisors (2188251).

28447081 is a wasteful number, since it uses less digits than its factorization.

28447081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2188250.

The product of its (nonzero) digits is 14336, while the sum is 34.

The square root of 28447081 is about 5333.5805046891. The cubic root of 28447081 is about 305.2665626271.

The spelling of 28447081 in words is "twenty-eight million, four hundred forty-seven thousand, eighty-one".