21128453329 has 2 divisors, whose sum is σ = 21128453330. Its totient is φ = 21128453328.

The previous prime is 21128453309. The next prime is 21128453363. The reversal of 21128453329 is 92335482112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10791054400 + 10337398929 = 103880^2 + 101673^2 .

It is a cyclic number.

It is not a de Polignac number, because 21128453329 - 2⁷ = 21128453201 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21128453291 and 21128453300.

It is not a weakly prime, because it can be changed into another prime (21128453309) 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, 10564226664 + 10564226665.

It is an arithmetic number, because the mean of its divisors is an integer number (10564226665).

Almost surely, 2^21128453329 is an apocalyptic number.

It is an amenable number.

21128453329 is a deficient number, since it is larger than the sum of its proper divisors (1).

21128453329 is an equidigital number, since it uses as much as digits as its factorization.

21128453329 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 103680, while the sum is 40.

The spelling of 21128453329 in words is "twenty-one billion, one hundred twenty-eight million, four hundred fifty-three thousand, three hundred twenty-nine".