28990705 has 4 divisors (see below), whose sum is σ = 34788852. Its totient is φ = 23192560.

The previous prime is 28990667. The next prime is 28990711. The reversal of 28990705 is 50709982.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50709982 = 2 ⋅25354991.

It can be written as a sum of positive squares in 2 ways, for example, as 10732176 + 18258529 = 3276^2 + 4273^2 .

It is not a de Polignac number, because 28990705 - 2⁹ = 28990193 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2899066 + ... + 2899075.

It is an arithmetic number, because the mean of its divisors is an integer number (8697213).

Almost surely, 2^28990705 is an apocalyptic number.

It is an amenable number.

28990705 is a deficient number, since it is larger than the sum of its proper divisors (5798147).

28990705 is an equidigital number, since it uses as much as digits as its factorization.

28990705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5798146.

The product of its (nonzero) digits is 45360, while the sum is 40.

The square root of 28990705 is about 5384.3017188861. The cubic root of 28990705 is about 307.1988547106.

The spelling of 28990705 in words is "twenty-eight million, nine hundred ninety thousand, seven hundred five".