28764215227921 has 2 divisors, whose sum is σ = 28764215227922. Its totient is φ = 28764215227920.

The previous prime is 28764215227897. The next prime is 28764215228003. The reversal of 28764215227921 is 12972251246782.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 22555746005521 + 6208469222400 = 4749289^2 + 2491680^2 .

It is a cyclic number.

It is not a de Polignac number, because 28764215227921 - 2²⁷ = 28764081010193 is a prime.

It is not a weakly prime, because it can be changed into another prime (28764015227921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14382107613960 + 14382107613961.

It is an arithmetic number, because the mean of its divisors is an integer number (14382107613961).

Almost surely, 2^{28764215227921} is an apocalyptic number.

It is an amenable number.

28764215227921 is a deficient number, since it is larger than the sum of its proper divisors (1).

28764215227921 is an equidigital number, since it uses as much as digits as its factorization.

28764215227921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13547520, while the sum is 58.

The spelling of 28764215227921 in words is "twenty-eight trillion, seven hundred sixty-four billion, two hundred fifteen million, two hundred twenty-seven thousand, nine hundred twenty-one".