28794721 has 4 divisors (see below), whose sum is σ = 28829332. Its totient is φ = 28760112.

The previous prime is 28794707. The next prime is 28794739. The reversal of 28794721 is 12749782.

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 8643600 + 20151121 = 2940^2 + 4489^2 .

It is a cyclic number.

It is not a de Polignac number, because 28794721 - 2¹⁹ = 28270433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28794761) 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, 16026 + ... + 17731.

It is an arithmetic number, because the mean of its divisors is an integer number (7207333).

Almost surely, 2^28794721 is an apocalyptic number.

It is an amenable number.

28794721 is a deficient number, since it is larger than the sum of its proper divisors (34611).

28794721 is an equidigital number, since it uses as much as digits as its factorization.

28794721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34610.

The product of its digits is 56448, while the sum is 40.

The square root of 28794721 is about 5366.0712816734. The cubic root of 28794721 is about 306.5050433524.

The spelling of 28794721 in words is "twenty-eight million, seven hundred ninety-four thousand, seven hundred twenty-one".