28220773 has 4 divisors (see below), whose sum is σ = 32252320. Its totient is φ = 24189228.

The previous prime is 28220761. The next prime is 28220779. The reversal of 28220773 is 37702282.

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, and also an emirpimes, since its reverse is a distinct semiprime: 37702282 = 2 ⋅18851141.

It is not a de Polignac number, because 28220773 - 2¹⁷ = 28089701 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28220779) 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, 2015763 + ... + 2015776.

It is an arithmetic number, because the mean of its divisors is an integer number (8063080).

Almost surely, 2^28220773 is an apocalyptic number.

It is an amenable number.

28220773 is a deficient number, since it is larger than the sum of its proper divisors (4031547).

28220773 is an equidigital number, since it uses as much as digits as its factorization.

28220773 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4031546.

The product of its (nonzero) digits is 9408, while the sum is 31.

The square root of 28220773 is about 5312.3227499842. The cubic root of 28220773 is about 304.4549002404.

The spelling of 28220773 in words is "twenty-eight million, two hundred twenty thousand, seven hundred seventy-three".