28820641 has 4 divisors (see below), whose sum is σ = 28833984. Its totient is φ = 28807300.

The previous prime is 28820639. The next prime is 28820651. The reversal of 28820641 is 14602882.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28820641 - 2¹ = 28820639 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28820651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2605 + ... + 8026.

It is an arithmetic number, because the mean of its divisors is an integer number (7208496).

Almost surely, 2^28820641 is an apocalyptic number.

It is an amenable number.

28820641 is a deficient number, since it is larger than the sum of its proper divisors (13343).

28820641 is a wasteful number, since it uses less digits than its factorization.

28820641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13342.

The product of its (nonzero) digits is 6144, while the sum is 31.

The square root of 28820641 is about 5368.4859131789. The cubic root of 28820641 is about 306.5969841413.

The spelling of 28820641 in words is "twenty-eight million, eight hundred twenty thousand, six hundred forty-one".