28573817221 has 2 divisors, whose sum is σ = 28573817222. Its totient is φ = 28573817220.

The previous prime is 28573817191. The next prime is 28573817329. The reversal of 28573817221 is 12271837582.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19716372225 + 8857444996 = 140415^2 + 94114^2 .

It is a cyclic number.

It is not a de Polignac number, because 28573817221 - 2²¹ = 28571720069 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28573817021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14286908610 + 14286908611.

It is an arithmetic number, because the mean of its divisors is an integer number (14286908611).

Almost surely, 2^28573817221 is an apocalyptic number.

It is an amenable number.

28573817221 is a deficient number, since it is larger than the sum of its proper divisors (1).

28573817221 is an equidigital number, since it uses as much as digits as its factorization.

28573817221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 376320, while the sum is 46.

The spelling of 28573817221 in words is "twenty-eight billion, five hundred seventy-three million, eight hundred seventeen thousand, two hundred twenty-one".