28228011520221 has 12 divisors (see below), whose sum is σ = 40797486360540. Its totient is φ = 18807739604160.

The previous prime is 28228011520217. The next prime is 28228011520229. The reversal of 28228011520221 is 12202511082282.

28228011520221 is a `hidden beast` number, since 2 + 8 + 2 + 280 + 1 + 152 + 0 + 221 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 14140525431321 + 14087486088900 = 3760389^2 + 3753330^2 .

It is not a de Polignac number, because 28228011520221 - 2² = 28228011520217 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28228011520229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 911212206 + ... + 911243183.

It is an arithmetic number, because the mean of its divisors is an integer number (3399790530045).

Almost surely, 2^{28228011520221} is an apocalyptic number.

It is an amenable number.

28228011520221 is a deficient number, since it is larger than the sum of its proper divisors (12569474840319).

28228011520221 is a wasteful number, since it uses less digits than its factorization.

28228011520221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1822457116 (or 1822457113 counting only the distinct ones).

The product of its (nonzero) digits is 20480, while the sum is 36.

The spelling of 28228011520221 in words is "twenty-eight trillion, two hundred twenty-eight billion, eleven million, five hundred twenty thousand, two hundred twenty-one".