28084428528221 has 4 divisors (see below), whose sum is σ = 30244769184252. Its totient is φ = 25924087872192.

The previous prime is 28084428528209. The next prime is 28084428528259. The reversal of 28084428528221 is 12282582448082.

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 1203158896996 + 26881269631225 = 1096886^2 + 5184715^2 .

It is a cyclic number.

It is not a de Polignac number, because 28084428528221 - 2⁶ = 28084428528157 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 (28084425528221) 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, 1080170327996 + ... + 1080170328021.

It is an arithmetic number, because the mean of its divisors is an integer number (7561192296063).

Almost surely, 2^{28084428528221} is an apocalyptic number.

It is an amenable number.

28084428528221 is a deficient number, since it is larger than the sum of its proper divisors (2160340656031).

28084428528221 is a wasteful number, since it uses less digits than its factorization.

28084428528221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2160340656030.

The product of its (nonzero) digits is 10485760, while the sum is 56.

The spelling of 28084428528221 in words is "twenty-eight trillion, eighty-four billion, four hundred twenty-eight million, five hundred twenty-eight thousand, two hundred twenty-one".