28640973 has 4 divisors (see below), whose sum is σ = 38187968. Its totient is φ = 19093980.

The previous prime is 28640947. The next prime is 28640977. The reversal of 28640973 is 37904682.

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 not a de Polignac number, because 28640973 - 2¹³ = 28632781 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28640977) 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, 4773493 + ... + 4773498.

It is an arithmetic number, because the mean of its divisors is an integer number (9546992).

Almost surely, 2^28640973 is an apocalyptic number.

It is an amenable number.

28640973 is a deficient number, since it is larger than the sum of its proper divisors (9546995).

28640973 is an equidigital number, since it uses as much as digits as its factorization.

28640973 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9546994.

The product of its (nonzero) digits is 72576, while the sum is 39.

The square root of 28640973 is about 5351.7261701249. The cubic root of 28640973 is about 305.9585466509.

The spelling of 28640973 in words is "twenty-eight million, six hundred forty thousand, nine hundred seventy-three".