28945099921 has 2 divisors, whose sum is σ = 28945099922. Its totient is φ = 28945099920.

The previous prime is 28945099907. The next prime is 28945099949. The reversal of 28945099921 is 12999054982.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17500379521 + 11444720400 = 132289^2 + 106980^2 .

It is a cyclic number.

It is not a de Polignac number, because 28945099921 - 2¹⁷ = 28944968849 is a prime.

It is not a weakly prime, because it can be changed into another prime (28945099321) 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, 14472549960 + 14472549961.

It is an arithmetic number, because the mean of its divisors is an integer number (14472549961).

Almost surely, 2^28945099921 is an apocalyptic number.

It is an amenable number.

28945099921 is a deficient number, since it is larger than the sum of its proper divisors (1).

28945099921 is an equidigital number, since it uses as much as digits as its factorization.

28945099921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4199040, while the sum is 58.

The spelling of 28945099921 in words is "twenty-eight billion, nine hundred forty-five million, ninety-nine thousand, nine hundred twenty-one".